Whats wrong with the Xperia series? I don't know too much but I like the Xperia Play when I got my hands on it and I think the OS is pretty much basic Android. Did I miss something? HTC is nice but I think at the beginning the HTC sense sytem could be a little confusing....
never tried Xperia Play.
my sister has an Xperia X8 and it keeps shutting down itself everytime. Same problem on the phone of my Drummer (Xperia Mini Pro)
So I'm not that into Xperia ;)
The new Sense 3.5 (wich is on rhyme) looks very tidy
but anyway everyone should try some systems in a phone store, so he/she can figure out wich he/she likes most