flash - does it matter which one?
If you don't have much experience with flash photography, the best bet would be to use OEM flash units. SB700 may be right on the value side - don't forget you get correction filters in the box (dedicated and "real"). I have SB600 but buying couple sets of CT filters and Tupperware (difuser) had brought it very close to what I was meant to pay for SB800 at time, which had all these inclusions in the box. Plus much more.
People are saying good things about 3rd party units. Metz is certainly reputable flash maker, but I don't think going that route would actually save you any money. Nissin has been praised for good value for money, yet some users have mixed results with different model of cameras. Once you get a grip on flash photography, you could do almost everything (but FP) with reliable non-TTL Auto flash. But first things first.