Yeah, I guess visually you can make the GUI on Foobar2k quite stunning 
I was suggesting that some features available on mediamonkey are not offered on foobar (or at least I think.)
I am pretty sure you cannot sync on foobar. MediaMonkey, however, does offer syncing for many media players (excluding apple products, at least to my experience). I have used it for a Sansa Fuze and it works fine. I have not tried any other media players, but I am pretty sure MediaMonkey will fit your needs.
As for myself, I use MediaMonkey to organize my files. It is extremely easy to tag files and add album art in MediaMonkey. I also use it to convert my music into a lower bitrate for my portable players. I can also auto-organize and rename my files (although I am not sure if this is available in the freeware version). Nevertheless, I use foobar for playback on my desktop, just because the interface is quite simple. Both are freeware, so I suggest trying both, and seeing which one you like more.
I would approach iTunes with some caution, however; it tends to run very sluggish and I don't really like the interface. Try it, though, and see whichever program you like the most :) . I would suggest using MediaMonkey for syncing your players, however.