Hi there and welcome to the forums, Assassin! Your name certainly reminds me of a class job in a game that I used to play, it was my favorite amongst all. :3
I'm not a competitive battler as well, but I hang out in PO sometimes because I enjoy battling, I don't take it really seriously though as much as others do. I just pick out random Pokemon and random skills! I've tried Challenge Cup before and it was really fun! I love the whole system. PC actually has it's own PO server as you can see, so it'll be much easier especially for new members like you to get to know more about your fellow PC members here as well as for an easier match/battle! Megan already linked you to the board, so I guess it wouldn't be much of a problem, eh? :D
So you play hacks? Well then, you absolutely joined the right place. As you can see, PC have the most English ROM-hacks and is basically one of the largest ROM-hacking board in the web! Some of PC's most-known ROM-hacks are Shiny Gold, rijonAdventures, Liquid Crystal and a lot more! Miss Doronjo already linked you the URL to go to the Emulation section, you could find a thread there containing list of completed hacks, so take your time to explore the whole board!
RP seems lots of fun, I've tried it before, although stopped because I don't have much time anymore. But yes, PC has a huge and active RP corner, so just check it out! You can also meet lots of awesome people there and possibly make a whole bunch of friends! :]
I know that you'll have lots of fun here, but before anything else. Keep in mind the rules as always, since that will keep you immune from the troubles that you don't want to get yourself into! Feel free to drop by and leave a message on my profile if you'd like to talk by the way. And so, enjoy your stay and see you around! ^__^