While not questioning the L series quality and prime over zoom I wonder what benefits a 24 mm (38mm at 1.6 crop factor) will give you. There are a number of cheaper alternatives and for this I would use the 24mm end of my 24-105 f4 Canon lens or the upper end of a 10 24 Sigma f4 I have.
In my opinion and I am no expert really, other than a 30 1.4 Sigma prime I have for portrait stuff a prime lense may better at mid-long focal length
I wouldn't bother with a 24/2.8 to be honest. If you are looking in that focal range and price bracket, you'd be better off with a 28/1.8 or 35/2. The Sig 30/1.4 is one level up from that and then the wide, fast L lenses (24/1.4 & 35/1.4) are on a different plane entirely.
That is one sweet lens and it has a reputation for being tack sharp. Landscape photographers swear by it and it is extremely useful for other situations like interiors. It was the first L glass I bought and would never want to part with it.
I had better start saving. Anyone want to buy a D60 (read my lips, a D60 not a 60D ) with a Sigma 70-210 1:4-5.6, 8gb Kingston CF and two brand new batteries and charger? I love this camera - it's built like a tank and is in mint condition, sadly I just don't use it any more...