Full pipe and fuel management system are the extent of most street riders quest for power. With the Power Commander you will want a full custom fuel, and maybe ignition, map to get the most out of it. There are quite a few more ponies hiding in there than a downloaded map will get you.
I also headerwrapped my pipes with insulating fiberglass cloth wrap, good for a couple ponies.
Other common mod, although not a power mod, is a TRE (timing retard eliminator)
you can get a k&n filter, but todays Fuel Injected bikes have GREAT filters and this will not get you much if any power.... just a filter that can be cleaned and reused instead of replaced. i also feel they filter better than stock while keeping power the same.
You can gain what is percieved as more power by going to a 520 acceleration kit on the sprockets. This usually drops one tooth on the front and a bit of rotating mass from the drive line to give you more acceleration (less top speed though) and the feeling of more power.
Those are the most common mods