I would also throw in my vote for the Nexus, if it fits your bill give it a go. I grabbed the G1 on pre sale and loved it. I knew that Android was for me. The Nexus takes it to a whole new level. Since the G1 I have had several Blackberry phones, couldnt find the crack in the berry so gave them up. Tried iPhones from 3g to 3gs and I would still wander back to my G1. Eventually got a Nexus and havent looked backed since. I did try Winblows Mobile on the Dash 3g and the HD2 in between different phones and whatta ya know, back to Android.
If you can go without the keyboard its a no brainer IMO. My wife has a slide, this is her 3rd one now and all have had issues with MMS not working for some reason, I asked T-Mobile csr's each time I had to call and ask for a new one if others are having the same issue, out side of a network issue that caused the problem on all Slides they said no..but might be something to keep in mind anyways. The phone doesnt feel slow, or bogged down at all to me, really nicely done by HTC/T-mobile. You would be happy with it I would imagine, but its still not in the same class as the Nexus, period.