Congrats! I'm in a somewhat similar boat on the Optimus T, but before this I rooted a Mytouch 3G and went crazy with the custom ROMs, etc. A mix of newbie/veteran, I suppose. It's seemed like a bit of a different world so far with this phone - not as much available ROM-wise ... YET
I'll throw out a few ideas from my experiences with both phones:
To your immediate question, I second drewwalton19216801 and highly recommend Titanium Backup. In fact, this was much of the reason I rooted this phone. It is a polished and indispensable app, allowing you to backup, restore, remove, etc. apps AND data. As an example, I accidentally reset my phone while playing around with the custom recovery (read on here...) and was able to get the apps I installed back to the state they were in when i used Titanium (including saved passwords, open folders). Once you've got Titanium up and running, back up all your apps - especially the stock apps you intend to get rid of. Who knows - if you have to return the phone, you may want to load these back in. After doing this backup, you can use Titanium to uninstall the protected bloatware since you now have root.
HOWEVER, before you do this, you may want to consider flashing the custom recovery image if you have not (can't tell from your post if you did this, or just rooted). Check out the sticky on this topic. The Nandroid backup is a REALLY good idea to do before you start messing around with stock apps and such. I haven't tested a NAND restore on this phone yet, but i did it all the time with the mytouch and it was a great way to start over and "freshen" up the phone if new apps had slowed things down.
Since it sounds like you are just getting started, I would emphasize not to accept any over the air updates now that you've rooted. No experience with this, but bad things happen. Had to be said
Also, it looks like the custom ROM community for this phone is just gaining speed. I can't speak to much here yet, but perhaps check out the sticky, and be forewarned that custom ROMs need to be tested with specific phones before you can feel comfortable using them. I wouldn't rush into new ROMs yet as you are just getting started.
As for other root-ish apps to try out, SetCPU and Cachemate for Root might be two to try.
Hopefully that's enough to get you started. Have fun, but read read read the forums. Tons of great ideas out there.