I HIGHLY HIGHLY HIGHLY suggest AGAINST downloading the antivirus apps from the market place. 100% of the phones I see come my way with software issues, and anti-virus apps, when I remove the anti-virus app, it takes care of the issue. ABSOLUTELY SUGGEST AGAINST IT.
Better idea is just to read the description of the app, and reviews prior to downloading...
The problems you are having sound very much like a software conflict generally caused by a conflict...which is very often caused by a bad app that is just not written very well.
I can't wait for gingerbread either, but froyo, if you take care of your device correctly, works extremely well. People just often times take smartphone to mean superman phone - which is not the case.
Edit: Hard reset does correct these issues, back your contacts up to your SD card if they aren't on your GMAIL account (contacts>menu>import/export>export to SD card). Don't just re-install all your same apps indiscriminately when you do your reset, otherwise you're going to have all the same problems. Pandora is a known good music player try sticking with just one known good one.