IP Proofed T3: Learnean Lumi Warblade 1 with Iron Heart Surge and Moment of Perfect Mind.
You're a level 11 character with just 5 HD, but you explicitly can't die except from the Disintegrate spell. Sweet. Not too hard to get immune to that one spell. You also can't be blinded or dazzled, and you can just shrug off any other condition with Iron Heart Surge. MoPM should handle outliers. Also, you have a really sweet TWF-style ability.
Or, for a more normal game, Necropolitan really does just solve everything. Check out the blanket immunities:
A: Immune to every fort save effect that doesn't target objects. That's pretty much all of them (except disintegrate, darn it).
B: Immune to Mind Effecting. This includes all fear effects.
C: For classes that don't have large HD, tons of free hitpoints. By doing the ritual with a UA Variant Necromancer or Dread Necromancer 8 in an area with a desecrated shrine, you get D12+4 HP/HD. That's equivalent to a d6 class having 22 con.
D: Since you can completely dump Con, you can reduce MAD issues and make some classes completely SAD
E: Immune to ability drain, physical ability damage, and level drain. Now you can wield a lifedrinker... which is just about the greatest weapon ever (two negative levels per hit ROCKS! And it's roughly equivalent in price to a +2 enchantment!). Amazing for anyone who can generate lots of hits, and not bad for everyone else.
F: Immune to Poison, Sleep effects, Paralysis, Stunning, Disease, and Death Effects.
G: Immune to Critical Hits... as well as nonlethal damage if you care about that.
H: Immune (and in fact healed by) the entire Inflict line, plus Harm.
I: Immune to death from massive damage
All this for just 3kgp and a lost level (which can be gained back quickly). You're also now vulnerable to stuff that targets undead, but actually have boosted resistance to those things. And yes, using Disguise virtually guarantees that no one hits you with undead targeting stuff if you keep the disguise up all the time. Why wouldn't you? And now some poor Cleric will try to kill you with Harm and you'll giggle (but kill him quick before he thinks of using Turn Undead!). You even get +4 enhancement bonus to Str and Dex as a parting gift, along with Darkvision, and if someone creates Permanent Black Sand (easy to do, just kill someone with the Black Sand spell) you get Fast Healing 1d6 by putting some in your boots.
Another important thing to consider is that a Novice Ring of the Diamond Mind will run you 3kgp. Adding the effect to an existing ring is just 4500gp. Doing this on both your rings lets you have Moment of Perfect Mind and Mind Over Body... that's one guaranteed passed fort save and will save once per encounter. Assuming your encounters go quickly, that should be sufficient to protect you from anything save based. While you're at it, Boots of Sidestepping from Dungeonscape are also super cheap and will often completely protect you from anything that targets reflex saves. None of these are quite as good as full out immunity but they generally get the job done.
JaronK