If they still use the rubber speedometer cable guide on the front fender, that probably still breaks after a while (cheap to expensive options have been detailed elsewhere).
Occasionally the rear brake switch sticks on (mine was replaced under warranty).
If you don't like blued pipes remove the AI (does that still apply to FI bikes?).
The CDI might go on the fritz some day but I think the numbers are so low I wouldn't worry about it.
The kickstand kill switch can become corroded after a few years and cause your bike to shut off intermittently (but that's rare and easily fixed).
On older bikes the chrome is kinda crap, but presumably you're buying it to ride not to show. Mine doesn't look great but it hasn't peeled or rusted.
Now, I did have a bike die at 52,000 miles with undetermined electrical problems (still dead). But I've done a lot of custom stuff to the bike and it's probably all my fault somehow. When I adjusted the valves the first time it was a virtual comedy of errors (new valves can take 3 months to get from England). Other than the CDI failing (and fixed by Chy with a tube of RTV, BTW, as Woody can attest) I've had virtually no problems not caused by me.
