Did you restore any data with mybackup or titanium backup? I did and it prevented the 1.6 update from downloading. I had to do a factory reset and wait until 1.6 downloaded and installed before using mybackup to restore anything.
Do a factory reset on your phone and don't install anything that isn't from the market until you get your ota update. Leave your phone on and on 3g, not wifi, overnight too.
i didnt do any backups i just installed the sappimg.nbh from unlockr.com and after installation i did several factory resets i got nothing still havent got anything. tmobile even gave me a free 3g sim card since mine was about 5 years old.

. i do agree 1.5 does run alot better than 2.1 and 2.2 my gps picks up so much faster and locates me right away hopefully 2.2 runs smoothly.