Help me decide on my next lens

Have some change to spare, and if I don't lose my shirt in vegas in a couple weeks I am thinking about adding to my lineup.

I have three options I am exploring right now.

Sell my 70-200 2.8 IS and get the V2
Buy the new Sigma 35mm
Buy the new Canon 28 2.8IS.

The Sigma is the most expensive option, followed by the upgrade to the v2 of the 70-200 and the 28 2.8 being just slightly cheaper.

I currently own a 24-105, the 70-200, and a 300mm f4. (plus a 1.4ii converter) Would be using the lenses on a 5D2.

Thanks for any and all input.

Let me preface my statement by saying that I do not have any of the mentioned lenses that you are thinking of buying. That being said, I have actually been researching the same ones. My needs may be different then yours, so it really comes down to your needs. If you have the 70-200 already the upgrade will only give you slightly better IQ, and will fill any void. It looks like you are lacking in the fast prime area. The 28 is a slightly odd length, and not terribly fast (2.8). That sigma looks like a real winner for speed and IQ - That is what I would shoot for.

The 28/2.8 only gives you a 1 stop advantage over your 24-105 so to me seems completely redundant. Upgrading the 70-200 may make sense if you pixel peep, but I personally would be more happy with the Mk I and the extra cash or another lens.

Out of all those options, I'd say the Sigma makes the most sense since you don't really have any fast primes, and nothing faster than f4 on the wide end.

Why not get the 28 1.8?