1. Curse & Doom
2. Paralyzed
3. Disease & Plague
4. Poison
5. Blind

*Doom is rather obviously a top priority. Deathclock. Should probably deal with that 1st :P
*Paralyze is so frustrating it goes without saying. If you are stacked with enfeebles, the inability to continue getting TP via melee hits+Jumps eaten by paralyze means you cant remove the rest of your enfeebles.
*Plague is similar in that it slows down your WS so you cant get TP to remove more stuff.
*Poison, not 'usually' life or death.
*lolBlind.

Just use common sense. If you are a melee and suddenly have all doom/plague/para/poison/blind on you what order would you want your whm to get rid of them in to get you back in shape the fastest? DOOOOM>Para>Plauge>Poison>lolBlind.

Sure once in a blue moon poison is really crazy 100tic stuff, but what are the chances that you will ALSO be plagued/paralyzed on those rare mobs? (Crab NMs, uranites). Virtually none.