I was in the same dilemma as you are. I have a 50d and decided that I'm waiting for the 5dMK3, even if it's a year. I would suggest getting your lenses in order first, get some faster lenses, sell yours to upgrade. Instead of your 24-105mm, you should get the 24-70mm 2.8L and upgrade your 70-200mm f4 to the f2.8 version. Also invest in the 50mm f1.4, this lens is amazing. Once you have those, you will improve your low light shooting for the time being and be well prepared for MK3 when that comes out.
In regards to the 5dMK2, it's an amazing camera and the hi ISO performance beats my camera by leaps and bounds. Not to mention the movie mode. I do like having the latest and greatest and unfortunately, the current 5d is almost at the end of its cycle (assuming) so I'm holding off.
Having faster lenses will tide you over till the new beast is on the market 🙂