I got a "black" wand with about 1130dps which has a socket, some IAS and 1300 life on kill.
I dont have lifesteal or life on hit, but i feel that the 2000 life on kill and my pretty large (24 i think) pickupradius for healthglobes is enough to farm mp0.
However i want to evolve into the higher mp's ofc, so i'm guessing i need to invest into EHP items?
If you're Archon, higher MPs aren't very efficient until you get pretty high dps. I only farm MP2 and I have just over 200k. I think 250-300k is recommended to make the jump to MP3. If you don't care about efficiency, you can farm MP4 with 200k, it's just a lot more annoying than MP2. Also, I think Life Steal becomes even more important at higher MP because it takes longer to kill RD elites, so you take more damage and need to regen more life. For that, Life Steal becomes a lot more reliable. You can also carry around a second weapon with life steal, like a high dps 2h with 5-6%, to switch to for RD mobs if they are a problem. I prefer to keep the MP low because I hate losing the Magic Weapon buff from switching weapons.
Higher EHP also helps, though I'm only at 260k or so in Archon form for MP2 and it works alright, so for low MP EHP isn't a big issue.
For high MP, I recommend the CMWW spec, particularly the SNS varient that is the highest DPS varient. It requires a bit more gear than Archon but it's pretty easy to jump into MP5+, both for key farming and ubers.
There's also another Archon build floating around here meant for higher MP farming, but I don't know what it is atm since I prefer the CMWW build, as it does more effective dps than Archon for sustained fights.