Discus don't need low pH water, they prefer soft water, and that's mostly for breeding. 7.5 pH range and below is usually ok as long as the water isn't really hard. They are touchy about nitrates though, and obviously there shouldn't be any ammonia or nitrites in any tank.
The main thing with discus is to buy from a reputable breeder. There are a lot of TERRIBLE discus, they often aren't fed properly, they're bred indiscriminately and just poor quality in general, often they have parasites or other health issues. That's not what you want, you'll think you're just a horrible fishkeeper if you buy these fish since their survival rate isn't too good, they're sickly, and you WILL be overpaying even if they seem cheap compared to other discus.
If you ever decide to get into discus the best thing to do is RESEARCH how to tell a good quality discus from a poor quality discus and make sure you are buying from someone reputable.
Angelfish would be a really good choice for a 65g. They're more readily available than discus, cheaper and easier to take care of if you're inexperienced.
There are a ton of other cichlids to go for, it just depends on what type you like. I tend to go for the big aggressive ones, but I also have angelfish, africans, severums, and various other types.
I think the cichlids aren't supposed to have any other species in with them, which suits me fine, since I'm still going to be running my 10 and 20 for various tropicals. I'm not even sure if I can have a pleco.
Try to figure out the exact species you're buying. Everything I named above is a type of cichlid. They're highly variable in personality and care requirements. An oscar and an angelfish are both cichlids, and they're obviously drastically different.