Cichlids are very hardy, you'll enjoy them. But you have to know what you're getting yourself into before you buy these fellas. Most of them get huge, and I'm not sure a 75 gallon would be big enough. It would be decent if you only got a couple.
They like a pH around 7.0 if I recall. I know that Plecos and Clown Loaches are compatible with them, although I would not recommend this because all of them are going to get too big.
http://www.aquariumlife.net/articles...cal-fish/8.asp This is a good site for basic info on Cichlids. My brother used to keep a huge tank with about 10-15 Cichlids in it, but they all got too big and had to be given away, which is a common problem with Cichlids.
Cichlids like many-branched driftwood pieces, long leaves to hide under, Java Fern, long wavy plants to hide in when small, etc.
I'm not an expert with Cichlid so I'll leave the rest to someone else who can help you.