I can only comment on what I have. I bought my first DSLR (not my first SLR, I have been using a Nikon F601 for years), a 5D Mark III with 24-105 f/4 L and a Speedlite 600ex-rt. The system never ceases to amaze me, kudos to Canon.
The flash is worth it's weight in gold. Very easy to use, more than enough power, fast recharge and more features than I will possibly use.
If you have the budget, I would not hesitate in recommending you buy it.