On a budget, if you want new....I guess the Paul Buff (AlienBees or Einsteins) would be ok. There's a dozen reasons why I'm not particularly fond of them, but I'll admit that for a "beginner light setup" they'd be ok. If you're inquisitive and don't mind basic math (ie. ratios) then I'd opt for a Speedotron Blackline setup instead. I've seen 2400w/s packs and 2 heads go for as low as $500 before, usually around $700-800 though, with additional heads being around $150-250. Sturdier and more reliable in my experience...but at the cost of being much much heavier and cumbersome.
If you are new to lighting, and want to get something that will do the job (albeit with a couple quirks) then a couple Alien Bee's should be fine. New they're like $250-500 depending on which model, and their modifiers are pretty cheap too.
ETA:
If you go the Bee route I'd opt for:
A (Budget version): 2 B800, 1 B1600, Beauty Dish (white), 2 med. Softboxes, "Lite Mod" with Barndoors and Snoot add-ons, and a PLM umbrella. Oh and Cybersync trigger and receiver. That should cover most bases, and cost ~$1500-1600 (or maybe 200-300 less if you buy used)
B (slightly more expensive version) 3 Einsteins, BD, 2 Softboxes, Lite Mod and Triggers. Should be around $2k, maybe 1-200 more. Benefit of faster recycle, shorter flash durations (if you need it) and supposedly better color temp consistency (I wasn't impressed when I used them, but they were definitely better than the Bees)