lens recommendation

Attention photography nerds:

I currently have a Canon D30 with a basic 35-70mm f/3.5-4.5 zoom lens, and it’s pretty great for multi-purpose stuff, with one exception that is annoying me: it’s not very wide at all. With the 1.6x multiplier on the D30 CMOS sensor, even at 35mm, it’s really 56mm. So anyways, I am interested in making my next purchase (probably not any time soon – i am just researching) be a wider lens.

My question is: should I get a fixed, faster lens like the EF 24mm f/2.8, or should I save my pennies for a more flexible, wider zoom lens? I hear so many stories from people buying lenses they never use, so I want to err on the side of flexibility here rather than heading the direction of having a bag full of lenses. Thoughts?

UPDATE: In case anyone is interested. I am not really sure if/when I will ever buy a new lens, but when I do, I am thinking that for the short-term, I will get an EF 50mm f/1.8 II – it’s not any wider, obviously, but it’s a good, solid, fast lens that I think would go greatly with the D30’s 1600 ISO for low-light portrait photography and stuff, which I find myself doing a lot of.

Long term, I think I will save my pennies and maybe some day buy the EF 28-135/3.5-5.6 IS USM, which is a well-rounded zoom which isn’t TOO hideously expensive at around $400. But that’s way too rich for my blood these days.