Seagate 320gb 7200rpm Laptop Drive, Good or bad?

The drive's RPM will have absolutely no relevance to stability whatsoever. You most likely had some incompatibility problems. I'd forget about that.

Obviously most 7200RPM drives will be a fair bit faster than your current one. However, they consume a fair bit more power, so if you regularly use your laptop on the go it's something to consider.

With regards to capacity, only you really know what you need. Drives with higher capacities are sometimes faster due to having a higher bit density - this relies on them having the same number (or fewer) of platters. If you don't know what I'm on about have a google.

The 500gb one seems to be out of stock on the site you linked btw.

you should get a western digital instead they are said to last longer than seagates

The power consumption on both you link will be comparable. The difference between the two is not power consumption. The 500GB will be faster because of the "areal" density mentioned above.

I think the WD suggestion is not a bad one. Seagate has been having a rough go as of late. And regardless of what is said about having been resolved I need a little time to accept.

Price and performance wise of the two the 320GB is the better deal. Good luck.