Mac's hit on the major issues. Stick with the CyanogenMod and you'll be fine. Mac, when 2.1 comes out he'll integrate it into his mod. I've got a lot of bits and pieces of 2.1 on my 1.6 MyTouch3G because he integrates them in his mods. He's got mods out for the G1/MT3g and the Nexus One/Droid. Running his mods is the best reason for rooting your phone.
Keep your eyes open with Verizon, they will be announcing the Nexus One and the Incredible soon. Both are high powered phones and some say the Incredible is the Nexus One "done right." Neither have a keyboard which seems to be the chief complaint of the Droid. Even folks who like the hard keyboards complain Motorola screwed it up on the Droid. So if that's not your cup of tea the Nexus One and Incredible will be the way to go. The Incredible will come with HTC's Sense which the interface they park on the Android OS. If the modders get into the Incredible (very likely with Cyanogen) you won't have to worry about Sense.
Stay away from the Eris. Mac's right, it has issues. It was recently rooted but a friend at work bricked his and it's turning out to be a sketchy process that may not work right. Verizon's selling out their stock and that'll be it for the Eris.
Absolutely Android 5 Reasons to switch to CyanogenMod 5.0.5
CyanogenMod | Android Community Rom based on Donut tree.
CyanogenMod Forum -> Motorola Droid