I too am a fan of onboard LAN, integrated USB 2.0, and maybe even integrated ieee1394 like on some of the newer SiS chipsets(?). Onboard sound is a convenience for my non-gaming PCs but in the gaming one it always gets my SBLive. I recall seeing benchmarks showing that most onboard sound hurts framerates more than using Creative Labs' cards (haven't seen a review comparing the different chips/cards in a while though so maybe things have changed). I'm still using my Epox 8kha+ board which only has USB1 and integrated sound of some kind that has never been used. As long as Abit or someone still offers barebones motherboards with minimal integration I will buy those for my main PC, and integrated ones for budget/random boxes.
Onboard video again is a convenience I'd like to only see in budget OEM boards.
The one advantage of *some* onboard/integrated components is that they are not attached to the PCI bus and therefore effectively free up your PCI bus for your actual PCI cards. Yeah for most people this isn't very important but that 133MB/s is definitely one of the most limiting factors when it comes to I/O on current mainboards that lack 64bit PCI.
As for USB peripherals, I have a USB logitech mouse, USB2/firewire external drive case for a DVD burner or hard drive, camera cable, and cell phone charger.

Oh there's a USB printer but that's on another PC. However only the mouse is connected 24/7...
Gaidin
Edit: Shouldn't this be in Motherboards?