Lots of problems after upgrading

I upgraded to 10.5 and also upgraded to iLife 08, but have actually had lots of problems with both. Specifically the OS locking up and freezing when trying to shut down. I've had to manually power it off a lot since upgrading. Also, iMovie seems to lock up all the time. I'm constantly having to Force Quit the application, and after I do that, I usually have to power down the machine. The applicaiton goes away, but the dock still looks like it's on and the machine won't power down. I have to manually do it with the power button.

Also since then one of my USB ports stops working sometimes, usually when I'm plugging in my external drive to it. I have to shut the computer down, and leave it off for a minute or two before I turn it back on, otherwise it won't work.

Should I take it in the the Mac store? I tried reinstalling Leopard and restoring from Time Machine, but it hasn't made a difference.

Just to add a few more details, I'm using a 2.2Ghz MBP that I upgraded to 4Gb of Ram.

I would try doing a COMPLETE erase and install of Mac OS X 10.5 from the install DVD. From there, plug in your Time Machine drive upon first boot, and just restore your personal docs, photos, music, etc. DON'T import any of your personal settings or previous applications, go download the newest (and probably built-for-leopard) versions of these apps brand new from the web. If you've got any type of application enhancers (APE) or anything of that sort, Leopard will throw a fit. Try this and let us know how it works out.