Of course, these are all my opinions, but:
- if you are looking for a full Sense based ROM, similar to stock with better performance and even some of the least popular built-in apps removed, the latest Plain Jane or XTRSense 3.1 seem best. Ivan's Official 1.0 is also good but not updated with the latest updates provided in July.
- If you are looking for a ROM that has great performance, uses the stock HTC bits but not the Sense launcher, XTR 3.0.3 is great, and I've also tried and liked Tainted Tenzo.
- If you are looking for something without Sense, with stock Android, Eris LightningBolt 2.8 or Droid Does 1.1 are both very good.
I've tried just about everything, including Aloysius, Evil Eris, the Froyo ones (kaos and CELB Froyo, which are both still incomplete), but the four listed above are the ones I like best.
And, you can find 'em all here:
Droid Eris Android Development - xda-developers