As others have said, part of the reason for the success of Ipods is the fact that Apple have allowed / encouraged a whole ecosystem to build up around them.
BUT – be aware that some older docks work with 12v (firewire) rather than 5v (USB), and Apple in their wisdom have dropped support for 12v from new ipods (certainly touch, nano, not sure about classic).
The logic3 you linked to looks identical to the one I bought 3 years ago which doesn't charge my touch. You might want to check this.
FWIW I just bought this and IMHO it is better built than the logic3, looks nicer, and allows you to use the menus on the ipod better from the remote (only relevant if you have very good eyesight or sit next to it):
http://www.amazon.co.uk/PURE-i-10-Powered-Remote-Control/dp/B001HBIXSW/ref=sr_1_1?ie=UTF8&s=electronics&qid=1247573458&sr=8-1
Otherwise, you'll have to buy one of these "charge converters" (which I needed to make the touch work in the car):
http://store.apple.com/uk/product/TS696LL/A
20 quid from Apple stores, so some cheaper docks might not be so cheap when you factor that in (and after paying 200 quid to Audi for a car dock only to discover I needed this extra thing I wasn't too pleased).