My iPod video has been going strong since it first came out. However the li ion batttery is (with everything) doesn't hold a charge as long as it used to. It doesn't matter because I use it at my home rig in my room.
The batteries are replaceable.
With rockbox interface flac and custom eq is possible.
Drag and drop add music is possible with rockbox.
Ogg is also possible with rockbox.
I'd say the capacitated click wheel is pretty inovative

@klovknov
with any pdap, don't expect great sound with them from good headphones (ones meant for home use) you should just go with koss oporta pros, px100s, or some low impedance earbuds...
Edit: I frequently mod my iPod and the fact that it hasn't died yet amazes me...I'm considering upgrading to 240gB hdd on my video.... I guess it would be kinda pointless because I dontevej have that much music....
Guess it would be for the bragging rights :p