Anonymoose

What's your defense against Creeping Corrosion?

What would you think of using Silver Knight in here?

My rebuild of this deck will probably be called something like Dawn of Despair or something similarly overdramatic. Also, anyone reading this, expect me to post a deck with the capacity to do at least ten trillion (yes, that's 10,000,000,000,000) damage by turn four. I even have a name picked for it as well: Crimson Sky.

What happened to Blighted Agent? Also, in an Infect deck, I'm finding out that instant pumps can be the difference between defeat and last-second victory. Which is why I'm really starting to like Mutagenic Growth.

Grim Affliction, or Virulent Wound + Dismember might help.Also, with this kind of deck, Inexorable Tide would be just evil.

One last thing, for real this time. For hybrid-color cards, the Ravnica, Guildpact, or Dissension sets could be handy, and anything from Shards of Alara, Conflux, or Alara Reborn might be a good place to start looking for cards.

For a land card, I have two words to suggest: Ancient Ziggurat.
Alloy Myr for the mana.
Maybe Maelstrom Archangel if you can manage it, and if so, then why not Etched Monstrosity as well?
No matter what happens, though: Sword of Feast and Famine is your best hope in a 5-color deck.
Finally, try to stick to cards which use hybrid mana, or colorless cards whenever and wherever possible. Remember: for a 5-color deck to be workable, it has to manage to bring out the best features of all 5 colors, in such a way that each card strengthens or covers the weak points of every other card, and any 5-color deck without a high focus on flexibility of any kind is guaranteed to be slower than molasses.
Hang on, one more thing.
Fetchlands may be at least as good of a resource to you as hybrid lands, if not more, since without hybrid lands, you won't rely as heavily on getting an Amulet of Vigor to speed things up.
Good luck with the daunting but fun puzzle of making a 5-color deck.

Looking good here. You just gotta love Hand of the Praetors, it's so good it's evil.
Have you considered using Triumph of the Hordes? It might be good in some situations, and Virulent Wound might go well with your removal in this deck. Also, Grim Affliction can be nice to have around in certain dire straits if Hand of the Praetors is alive.
I'd like to know about any thoughts you might have on my own infect deck, because I think it could always use more development. As it's also my best deck, there may be a few useful ideas in there.
http://www.mtgvault.com/ViewDeck.aspx?DeckID=169126
There it is; my personal favorite deck. Input of any kind is welcomed.

I'm considering rebuilding this. I just need to get back my Serra Ascendants, and I'll try making it a lifegain/control deck. What else could I do with Norn's Annex, Elesh Norn, and all those other neat little Phyrexian cards? Suture Priest could be nice.

That does look like some sound advice for this deck. Were there any specific pumps you had in mind? I'll look around in the mean time for some pumps. Although, I may need a little damage prevention, at least in sideboard, to keep me save from the local FNM champ and his Deciever Exarch/Splinter Twin infinite damage combo.

Thanks for the good input. I'll keep looking for more Crusaders, and see what I can do to find another Skithryx and some Inkmoth Nexus.For starters, I'll experiment more with creature removal and instant pumps like you said. I think that could really add a lot of power to this deck. After the next FNM I go to, I'll make a post saying how it performed.

I like what you did to make Persist work forever, using Melira to prevent -1/-1 counters. Is there anything in here to guard against instants that use your own creatures against you in here?

Karn Liberated. For the first time in a while, I decided, "Why not buy a booster pack and see what all the fuss is about with this new set?" I bought a pack for $3.00. And there was Karn, staring me in the face. It's the one card that everyone I know has offered to trade me massive amounts of cards for, and has never lost me a match, ever. And the backstory of the character is pretty much the most awesome thing I ever heard. I could go on and on and on and on, but I'll be nice and not take up the whole screen here with the rest of my memory. I'll just leave with this remark: since the day I put him in my deck- any deck, that's the great thing about him- I've been called a Karn-ivore because of the way I get to use him. Love that nickname.

ANNOUNCEMENT: Midnight Sun has changed- a lot. It turned into two decks; a W/U/B control/power-attacking deck and a G/B Infect horror show, both of which do really well. I think that now would be a good time to start rebuilding this deck from the maybe 90% of it I left behind in the process, and add things like Elesh Norn, Geth's Verdict, and some proper control and lifegain. Maybe make it a W/U deck insstead, and go for the total nasty control of a Dovescape/Godhead of Awe/Elesh Norn combo, turning all opponents' spells into a bunch of dead birds, and making even Emrakul -1/-1.
Thoughts, anyone?

Yeah, taking another look over this, I have to say, you probably would benefit from removing anything and everything in here that deals damage in any way other than poison or -1/-1 counters. Also, Proliferate is okay. Come to think of it, Spread the Sickness is possibly the perfect way to get rid of that annoying Melira, Sylvok Outcast.
Hang on- A couple more suggestions.
Blightwidow and/or Reaper of Sheoldred for defense, Grim Affliction and other Proliferate cards for the nastiness of it. Heck, if you have problems with Flyingcreatures, you may just want to go with Pistus Strike.
To sum up what I'm trying to say, try removing everything that doesn't help you poison opponents, and try not to add anything without the words "poison counter" somewhere on it.

Hand of the Praetors is good.
So is Triumph of the Hordes, and Inkmoth Nexus. I also might suggest Plague Myr instead of or in addition to Ichorclaw Myr,
Rot Wolf may not be too strong by itself, but opponents have a choice between taking 2 poison counters from it or basically letting you draw a card. Finally, I find I like Phyrexian Swarmlord a lot lately.
I hope some of these suggestions will help. If you feel like a look at another Infect deck might help you with ideas, feel free to browse http://www.mtgvault.com/ViewDeck.aspx?DeckID=169126
I call it "Ragin' Contagion", and its leading recommendation is that it consistently beats two tournament-quality decks I go up against.

I know this is random of me to drop in ike this, but I have this U/W combo someone absolutely has to try:
Godhead of Awe + Dovescape + Elesh Norn, Grand Cenobite.
Prevents spells from doing anything more than producing -1/-1 Doves, and sets all opponents' creatures to -1/-1 and yours to 3/3. Sound tempting to try? If you can do this and make it work, I say go for it, or tell someone who would be able to do that. It would be the most sadistic thing ever to come out of U/W control.

'Sup? My artifact deck's undergone yet more changes, and I know I'm asking you to help me improve my most rabidly powerful and hated deck, but remember: Since I did get a lucky find with the Karn, You now own our Nicol Bolas, so congratulations on that. I'll get it to you as soon as possible. Also, I'd like to make a trade offer: I have an extra of Vorinclex, Voice of Hunger. Is there any chance you might have a use for that one as well?

The Karn is just killing me here... The urge to try it out is almost irresistable, but I can't figure out what I could try swapping it with and not screw up the deck in the meantime. Any suggestions?
Heck, if anyone has any ideas about anything I could do to continue to improve this thing, they're more than welcome to chip in.
Nor would I mind if anyone asked me to do the same with their deck, since I can only learn more by seeing what others do with their cards.
Everything in my sideboard, I have and am considering for use in the main deck.

This is such a huge deck.