Every time I wished I had some new/different overdrive effects to play with on my 500x, I remember how much more practice I need.
Cruisinon is right BTW. It's been said a bazillion times, the 500 is old and we shouldn't expect Line 6 to still be investing in it. If you outgrew it, sell it and buy something newer with more to offer. Personally, I'm glad Line 6 continues to push forward and not focus on things they did 7 years ago.