yeah, I'd also say that there are many better options than Sector 9s. Sector 9 is a popular brand, but with a few exceptions (bomb hills, goddess of speed maybe)... the brand is very overrated and the boards are mediocre at best.
Looking in the same price range, Gravity makes better stuff. GF Hurley is another cool brand at a reasonable price point. Other good brands (that may cost a little more, maybe not...depending) are Fibreflex, Landyachtz, Motion, Earthwing, etc. There are some sweet custom brands out there like Longboard Larry, Insect, and Subsonic if you're interested, but that might be a bit excessive. Finally, as someone mentioned before... Loaded boards are a lot of fun, but pricey.
check out
www.silverfishlongboarding.com - it's a forum with lots of good info
www.milehighskates.com and
www.thelongboardstore.com are solid places to order gear
Let us know your budget and what kind of riding the board would be used for, and we should be able to give more specific suggestions.