There are hundreds of models; everything depends on your budget and features. I tried about a dozen, and all of them work fine with Voipo (note the comment about HD audio support in JacobsLive's comments). Ease of setup is inversely proportional to richness of features. For example, I was never able to configure second line (but frankly, I never needed it on IP phone, so I didn't try really hard).

On the cheap side there are Cortelco phones that are under $20 on Amazon - the sound quality is actually good, but you give up on a lot of features. However, most of the phone features take advantage of PBX functionality (eg., call parking, multi-line personality, etc.) that you don't have on a residential plan, anyway.

Good luck!