It is getting very annoying to have apps that are preinstalled take up space that I could be using for usefull ones so I am going to try to root my phone now. However, I am still very hesitant to do so since my phone is my main means of communication and if I mess it up I'm SOL.
I rooted mine on 64 bit windows, using Unrevoked. How could you do root privilege tasks without root? You cannot backup prior to root. Deleting bloatware from the phone after rooting WILL NOT clear up space.
You can backup some of the content before rooting, but you can't backup the entire stock ROM before rooting.
I rooted mine from an Ubuntu 10.10 32-bit box because I couldn't get UnRevoked to work on XP 32-bit or 7 64-bit. Ubuntu doesn't require any extra drivers like Windows does.
I think you might be confused about what UnRevoked does. Basically it uses a security exploit to gain root privileges, and then
replaces stock recovery with ClockworkMod Recovery. ClockworkMod is what allows you to do full ROM backups, among other things like flashing new ROMs, clearing caches, etc.
You asked about using the stock ROM after rooting. Yes you can do that; you are not required to flash a different ROM.
Also Akilldema is right about the apps. Uninstalling shipped apps does not free up any space for other apps because they don't share the same partition. Don't root it thinking you're going to free up a bunch of space by uninstalling shipped apps. There are other methods of saving space though. Read up about cMTD and Apps2SD. There are several methods of rearranging things to allow for more app storage.