so... what to buy next?

I'm getting a fair bit of work coming in; the odd wedding, a bit of journo work and some magazine stuff etc. and it's time to invest a bit of cash back into this little venture of mine, so...
Currently I'm carrying a couple of 40Ds with 50mm 1.8, 17-85mm 4/5.6, 70-300mm 4/5.6 and sigma 10-20mm but as my workload and hopefully reputation keep rising I need to make sure I'm doing the bookings justice.
Where do you good folk think I should splash some cash to keep things improving?
TIA.

f/2.8 zooms and/or large aperture primes. In no particular order:

17-55 f/2.8 IS
70-200 f/2.8L IS
24 f/1.4L or 35 f/1.4L
85 f/1.2L
135 f/2L
200 f/2L IS (if you really wanna go nuts )

Do you have flashes and brackets?

Replace 50mm 1.8, 17-85mm 4/5.6, 70-300mm 4/5.6,

with...

50mm 1.4,
24-105L
70-200mm your choice of L.

jr_senator wrote in post #7752397
Do you have flashes and brackets?

- yes - forgot to mention, plenty of flashes, cables etc.

Some great glass recommendations so far. Faster glass seems like the way I'd like to go but... so much to choose from

verdantsound wrote in post #7752428
Replace 50mm 1.8, 17-85mm 4/5.6, 70-300mm 4/5.6,

I agree.

verdantsound wrote in post #7752428
with...

50mm 1.4,
24-105L
70-200mm your choice of L.

Yes (but only if you need the extra two stops.
no, 17-55 f/2.8 One stop doesn't sound like much but many a time it makes the difference between getting the shot and getting something blurry.
yes, 70-200 f/2.8

How about a 1D Mark III ?.

I actually like the 50 1.8 more than the 50 1.4...don't burn the 300 $ if you can help it, I suggest keeping the 50 1.8. There isn't a real world of difference until you see the 1.2

maverick678 wrote in post #7752533
How about a 1D Mark III ?.

Heart says yes... Head says no.

cardboard....snoot? xD the 50 1.2 is nice xD

How about a EF70/200 F2.8L IS USM or a EF100 F2 USM