Hey i'm finnally making the move from sony to canon what i've been using is:
I'm upgrading to:
16gb Cf card
My predicament is weather to buy a 430ex ii with a couple triggers or a Tameron 28-75 2.8
I mostly shoot longboarding, landscapes a little bit of portraiture low-light events, day time events and quite a lot of video, but I really want to experiment with flash but not sure I want to lose the focal range capability for video or lowlight shooting, recommendations?
There were some comments about rather getting the 16-35 f/2.8. My view, rather is that you are missing a standard zoom. I would rather go for the 24-105mm f/4L IS USM than the 17-40mm. It is a little pricier, but the 24-105mm is probably one of the all-round most practical lenses. - Despite the fact that it is only a f/4, it is still very popular with wedding photographers. I would try to get the kit with the 5DII and the 24-105mm f/4L - that is very good value. The only downside of the 24-105 is that the bokeh is a little busy with certain backgrounds, and can be a little distracting.
Just another comment about the 17-40mm on full frame - for landscapes you need to use it around f/8 to f/11 to get any semblance of sharpness in the corners. This is an example:
http://www.flickr.com/photos/specular-images/7524804780/#in/photostream - Even at the highest resolution I have uploaded to flickr, you can see that the corners leave a bit to be desired - this was shot at f/16, so I would have lost a little sharpness to diffraction again as well. - In a 100% crop, the corners are mush. - I'm not trying to say the 17-40 is a bad lens - just understand its limitations. It is however a very usable walkabout lens for a crop frame body as well.
I would concur with the other posters about the need for a flash. Something to think about is the fact that Canon's 4x0 series flashes do not rotate through 360 degrees, which can be a problem when using bounce flash indoors.
I know it is a very expensive option, but also think about Canon's radio triggering system with the 600-EX-RT - it is an impressive system, just getting one Speedlite and a trigger already costs a bomb. - It may be worth considering taking the path of first buying a third party flash to get started, and then saving for a 600-EX-RT. That path, however, sees you committed to the Canon radio trigger system! - Make an informed decision, and understand the consequences of your decision. ;-)
One obvious gap in moving from your old kit is at the long end. Your 70-200mm on the Sony is equivalent to a 320mm at the long end on the 5DII.
What you probably need to consider is which aspect of your photography to concentrate on first. That will allow you to spread your purchases over time. If you can afford to keep your old camera while you start building up your new system, that may help you to still enjoy all aspects of your photography, even though your new system does not cover all of your interests.