08-04-2011, 11:11 PM
After thinking about it, I'd recommend migrating your stuff FIRST using Migration Assistant. THEN I'd say you should test at least a few apps to make sure everything came over okay (Migration Assistant has a stellar track record in this regard, but it never hurts to test).
THEN I'd say you should make at least a Time Machine backup, preferably both that AND a bootable clone backup (using SuperDuper
or Carbon Copy Cloner
). This would be the same advice I'd give someone who was staying with SL as well. You'll also want to boot from the clone to make sure it works as well.
Next, I'd suggest researching your most-used apps to make sure they'll continue to work in Lion -- the overwhelming majority should have no issue if they are up-to-date, I've been VERY pleasantly surprised by some older software I have that had no issues, but there are some packages that have issues and some older stuff that simply won't work at all (Rosetta dependent, etc). Roaringapps.com is a good place to start that research.
Finally, at this point I'd buy and download the Lion upgrade, make a backup of the installer for future burning to DVD or USB stick, and upgrade to Lion. I'm making this sound like a much bigger deal than it actually is, but backups are ALWAYS a good idea no matter what.