I have both lenses you have mentioned. I hardly ever use the 50mm anymore because I usually produce travel photography and I have found in the past that using a fixed length lens made me miss out on lots of photo opportunities. Changing lenses in harsh conditions is also not an option due to the sensor dust issue. With a zoom lens it's also easier to make different images of the same subject which is not a bad thing when doing stock photography.
But as Afagundes pointed out, it's all about what and where you're photographing. If you're doing studio photography, you might want to go for the 50mm. If you're mostly photographing outdoors, I suggest you buy the 24-105L.
Are you using your 50mm f/1.8 lens a lot? If you are - see if you can fix it and save the costs of a new lens. If fixing it is not an option/not worth it but you have been using the lens a lot, perhaps the f/1.4 would be a welcome upgrade. The extra light it lets through will be useful.
I wouldn't compare the 50mm f/1.4 vs the 24-105 f/4. Chances are, a lot of people might have and use both. The 24-105, however is well over 2x the price of the 50mm. You already have a wide lens, as well as a telephoto zoom. Perhaps the 50mm f/1.4 would be a better choice, but only if you see yourself using it regularly.
I broke my 50mm f/1.4 by accident (and beyond repair) and soon after bought a new copy. I'm using it quite often and the price was the only reason why I didn't get the f/1.2L version instead.
Thanks all....going to try and see what is happening with the focusing. If it can't be fixed..well so be it.
I do use the 50mm a lot but I often find myself limited in space with this lens on the 60d body with crop sensor. Have had two shoots for example where I find myself with my back to the wall literally and I need just that 3 feet extra.
Petarneychev, will maybe look into the 1.4 later then.
I think the answer is simple - if you need f1.4 (at this specific FL) - either for subject separation, or for lack of light, then go for it. If not, stay with zooms, as they can produce almost the same quality, and are more versatile.
I'd only suggest to stick to lenses designed and optimized for crop cameras (unless you plan to upgrade to full frame very soon); also, 24-105L will have too much overlap with you 70-200. My personal choice would be Sigma 17-50mm f2.8 OS (I bought one to replace my kit zoom + nifty-fifty); but Canon 15-85mm IS is also highly regarded, and would cover nicely FL range for you.
Hey guys...thanks for the input. Yes I would love to have the 24-70...but they are soooooo expensive.
Pulsar I am planning on going full frame in the future when the opportunity comes along. Just this afternoon I was wondering if I shouldn't rather just go full frame instead of messing around with lenses. I am happy with the quality my lenses are giving me. That way I can still use both the 50mm and 70-200. Just need to sell the 10-20 sigma.
Siggy is great - my mostly used lens. IS is very helpful, IQ is great, AF is fast.
If you plan to move to FF say in 6 months or less, probably no point in buying more crop lenses. If it's more like in one year, I'd still buy Siggy - probably a used one, so you won't loose much by reselling it.