I have fallen in love with montipora caps. I only have two right now and I want to get even more. They grow relatively quickly. One of mine have quadrupled in size in just 6 months. And also something else I like is the birdsnest, although I'm not too sure on its growth since I just got it about 3 weeks ago.
There are 3 main varieties of montis - caps (the big plates), branching (these look like acroporas), encrusting (these grow over the rockwork and have colorful polyps). The encrusting are slower growers and are a bit more challenging.
I would really recommend monti's as starter SPS's.
As for acroporas/SPSs - there is a dizzying array of these and some are more difficult than others - you will have to do your research. Some of the easier ones (imo) are birdsnests (seriatopora's) and green slimers (yongai).
Start with frags (clipping) - you can get them for probably around $10. That way you will know if your tank is ready. Its fun watching a frag grow over time.
I think birdsnests are also pretty easy SPS to start with. Once your tank has matured, then think about adding some acros. I have both red planet and tricolor acros in my tank which I love!