Backup Strategies / Suggestions?

Hey folks,

I'm looking for some suggestions on backup strategies. Some background - I have 2 Mac's, one XP machine(soon to die) one Vista machine on my network. I have a 250GB portable USB drive and a 250GB NAS. At this point all of my data is replicated in 3 places (XP, USB Drive, NAS).

I bought an AEBS with the assumption that I could share NAS devices and back up with TM. As it turns out, we can't. So, yesterday I bought a TC, but after reading some reviews of it, I'm nervous as heck to disconnect my perfectly good AEBS and try the TC.

My goal is to have a network or shared drive with all of my data on it and another network or shared drive as a backup. Is the TC an option or should I just buy another NAS and install some backup software on the Mac to copy files from one NAS to the other periodically?

 

So, do I set my NAS to backup to my TC, or vice versa? Can Time Machine do that? I'm trying to get away from having all of my data on my MBA becase the drive is small.