i'm sure one of the older guys have a better answer for you, but i'm pretty sure they'll keep for a while. i've had mine for a month or so and it's been fine. not much experience keeping them longer than that.
i made a hefewiezen and a cream ale, but what really got me hooked was an oatmeal stout... try one of those bad boys... amazing beers. Since that one I've had a hard on for all stouts, trying any stout I could. I'm brewing a chocolate stout right now. Just an idea...
my first brew i couldn't wait. it gets easier to wait once you get a pipe line established. actually my first two brews were a week in each and they tasted awesome. my third and fourth went longer, and now i have a few going so it's no big deal.