On the bright side, you wouldn't find very many Psychic types floating around (at least compared to, say, Dragons and Water-types). If your Gengar is fast enough, it could even take one psycho down before it even attacks. If you really want Hitmonlee, there's no one stopping you. It's pretty good nonetheless. Heck, I've won a local tournament once using only bug pokemon XD With the right planning, you can make both work well against any odds.
Anyway, aside from the sweepers, you might want some kind of Tanky poke or something that you could use just for trollgasmic fun. Good choices are those that use the moves Toxic spikes, spikes, leech seed, and stealth rock. Recover, Giga Drain, and the likes help make these movesets more useable.
Toxic+recover/protect work wonders, too. You might find it fun to use even in non-competitive battles once in a while.
Try new kinds of combinations, having a variety of pokemon in your team could make your experience a lot more fun.