I have a mini 9 that has ubuntu 8.04 on it.  For various reasons, i would like to wipe my computer clean and install a new version of ubuntu on it.  I realize that the version of 8.04 that came with my computer was a version configured to the particular chip on this computer and have read references to compatibility problems if installing ubuntu versions that are not designed for the Dell.  I also have no experience installing ubuntu from a flash drive, which is what I am thinking I will have to do. I am moderately computer savvy, but not particularly Linux savvy.  So a couple of questions:

1. What version of ubuntu should I be using to minimize problems and where best to download it from?

2. I am sure I can poke around and find instructions for installing Ubuntu off a flash drive - but if someone can direct me to a good set of such instructions it will be a time saver.

3. Any other advice to simplify this task?

Thanks.