Hi and welcome back to the sport.
At 5'9 I would say that you may need a medium frame. It is in your best interest to get fit to the size you need at your local bike shop, if they offer that service. Most do.
Hardtails with front suspension come in entry level, intermediate, and race level. Entry level there are some choices in that price range. Intermediate, or a bit more durable fork, you'll probably be looking around $500/$600. If this digs into the budget too much there are some good used buys out there and advice will be all across the board here, but parusing through you will find good information.
Components wise I wouldn't go with less than LX in Shimano, or X7 in Sram. A lot of entry level bikes have the Rock Shox Dart fork which is okay, and your weight shouldn't be a factor, but likely the single most important detail is buy the most quality that you can afford. In the bike world price directly reflects durability and quality - for the most part. Example by that I mean dollar for dollar I can't see the need for XTR over XT unless you have the cash to spend and want it.
First and foremost is fit. If the bike doesn't fit properly (correct size for you) no amount of components will make it right.
Hope this helps.