Sansa e280 with Rockbox (or whatever it's called) was probably the best and my ultimate favorite so far. Too bad I don't have one anymore, fuckin' thing died on me. Probably had the best organization menu, lagless interface, and features that blew my mind at the time. Price extremely reasonable.
Sansa Fuze+ 16 GB, with a 32 GB MicroSDHC is what I have right now, holds a crapload of songs but organization is too complicated. Interface is very laggy, and touchscreen has some problems responding sometimes. Really good on battery life, and it let's me set my own photo background, add videos etc... Price somewhat reasonable.
iPod Classic (6th Generation, 160 GB) Held the most music, great quality, fast interface, sensible organization, honestly not a terrible price either. Downsides is it's ugly look, and overall clunkiness that makes it less-than-attractive.
iPod Nano (7th Generation, 16 GB) Held a less than palpable amount of music, look and size was MUCH better than that of a classic, interface was lagless (to my experience.) Price a tad bit high.
Honestly I'd like the e280 with rockbox if it could support my 32 GB MicroSDHC, doubt it but it's possible that it may (it did with a 16 GB back then, but that was pure luck at best I believe.) This is if I could have a choice to get a new one, without price being a problem.
I'd give my review on an iPod touch if I actually had one.
Products to avoid: RCA, Samsung, LG.
The Sansa Fuze (Regular) is terrible and hardly works, if you put too much music on it it'll crash, hang, and constantly screw up.
Archos 5 Internet Tablet (16 GB) was probably my favorite tablet of all time, I got one refurbished and it lasted quite longer than I expected it too. Worked with MicroSDHC, and damn 1080p videos looked good on it. (Browser kinda sucked though, and it didn't support later versions of Android.)
Other than that really haven't had much, I'd use my phone but honestly it's crap. Does everything most smartphones do nowadays though.