I've been rollerblading for about 10 years, and love it. My advice:

-Get a good skate. Cheap skates are dangerous, heavy, uncomfortable and much less enjoyable. Specialized sport, trick or speed skates aren't necessary - you ARE a beginner, don't flatter yourself - but a really solid, $200-$400 pair of skates that you've taken real time to pick out are worth it, and with a bit of maintenance will last you a few years at least.

-For speed, stability, shock protection and ability to handle poor terrain, get a skate that uses big wheels. Soft wheels are an excellent shock protection solution, but they wear down much faster, and a new set of wheels can run you quite a hefty sum of cash.

-Get a skate designed to handle urban terrain at speed. I have a pair of K2 Soul 7s, and I love 'em! They have a leather inner boot, which makes them very comfortable, and a large metal truck (metal for sturdiness, and large to hold big wheels).

-Heel brakes are bad. They're dangerous and awkward to use, and dangerous to have on your skates, because they catch on stuff and trip you. If your skate comes with a heel brake, remove it, and learn to stop by dragging your back foot behind you, forming a T with your forward foot, and putting pressure on your rear foot. It's scary at first, but once you learn it, it's a much better, easier and safer way to stop.

-Pads! Helmet! Use 'em. A good light set of pads is a helmet and wrist guards - wrist guards are the most important pads. I don't wear pads, but I probably should, even though I'm so experienced.