I wouldn't limit yourself to just softies simply because it is your first tank. I might look into lps as well and put some acans or something in as well. Acan lords and favia are pretty easy to keep, can be very colorful, and often have similar requirements as softies do in regards to water nutrients and light. Down the road, once your tank gets more stable, depending on the nutrient levels of your water, you might also consider sps. I would consider cyphastrea. It is a fairly easy to keep fast growing encrusting sps, and most types of it do well in lower light levels. Other easier to keep sps are birds nest, montiporas, and stylophoras. These types of sps need moderate lighting and flow, grow fast, and are very hardy. Also, you can get most types of these fairly cheap and aquacultured, or perhaps even free from another hobbyist if your lucky.