Question on what's the best lens to use....

I have a Canon 30D that I bought almost a year now and I'm wondering if anyone can give me a suggestion on what lens to buy and use for an event that I'm going to. I'm going to a car/drift show and it's going to be at night and outdoor. I have just the regular lens that came with the 30D and I haven't bought any lens yet. Also, what's the best lens to use on a very low light condition inside a convention center. I know I need to buy a lens and I also need to buy a flash which I'm thinking of getting the Canon 580EX, if I can find it at Ritzcamera.com
Thank you so much and I hope someone can give me some advice.

first, welcome

given the HUGE difference in price in lenses available, it helps to know what kind of budget you have to work with. ....you could spend anywhere from $80 to $6000

a good one to use indoors would be a prime lens (doesn't zoom) with a wide, constant aperture setting.....canon's 50mm f1.4 would be a good contender at roughly $300, but a 50mm could definitely be a bit long for indoor use...

sigma makes a lens that is 30mm and f1.4 that would work pretty well in the convention center, it's $364 at sigma4less.com. you can take very nice pictures indoors in low-light conditions even without a flash with that lens. or canon makes a 35mm f2 that goes for sub $250 i think....

not sure about the car/drift show but the sports guys will answer that soon i'm sure.

Ideally I'd want to use the 200mm 1.8L

So just run a long a pick one of those up.

Ritzcamera.com is pricey on photo gear, why there? Regardless of which camera you have now or in the years to come the 50mm f/1.4 would be an asset in most anyone's bag. It's next on my list after I recover from the 1D3 I am getting in June.

Thanks for the welcome and thanks for the replies. Ritzcamera.com was one of the first site that I started looking at for lens and flashes. I'm still searching for cheaper places of course. Thank you for all your suggestions so far.

try b & h or adorama for cameras lens etc.

..... given the HUGE difference in price in lenses available, it helps to know what kind of budget you have to work with. ....you could spend anywhere from $80 to $6000

Or even more (see my avatar) which, by the way, would work for this event...

Jarrad wrote in post #2943076
Ideally I'd want to use the 200mm 1.8L

So just run a long a pick one of those up.

Or the 400 2.8.. Maybe B&H will cut a deal if you get both...

Given that you have gone well with the kit for a year now.... I would probably go with the sigma 30 1.4 (low light) and a flash the 430. Order online!!! it'll save you "beaucoup" $....