Thumbs up to the Treo 650. I had a Treo 600 for two years and replaced it under warranty four times. The Treo 650, so far, seems much more stable, is significantly faster, and has a beautiful screen. The biggest downside is the memory issue (written about everywhere), but a utility called PowerRUN and a complimentary 128 meg card provided by palm seem to have solved this problem reasonably well.
A qualified thumbs up to Snappermail also, which is significantly better than the buggy Versamail. The biggest downside is the annoying habit of laboriously highlighting every link in every email, which makes trying to scroll through quickly a pain in the ass. Snappermail support has been appropriately sympathetic and perhaps they will change the scrolling system in a future release. (I should mention that these entries are emailed to kidneynotes using Snappermail on a Treo.)
Also thumbs up to adobe reader for palm, avantgo, treo butler, datebk5, documents to go, epocrates, filez, holidates2, lifebalance, and everything on statcoder.com.