Update on my music tab issue: After cross checking with other threads it seems that this is an issue with Sense 2.5 itself. What happens is that while the song plays, HTC Music checks Gracenote for album art (the spinning circle in the upper left corner). Then (I'm guessing) some error happens that stops playback if you don't have the right album cover or whatever. I'm going to flash beta4.1 in a couple of minutes and delete all the album cover jpgs from the My Music directory and see if that makes any difference.
I guess one solution would be to cook the 2.1 or 2.0 music tab into future ROMs (I have no clue at all if that can even be done- the experts can call me a n00b), because those versions don't have the Gracenote feature. But... if I'm the only one with this problem, I won't cry too much if I don't get my way.
In any event, thanks for the input and I freakin' love this ROM!