Hi folks,
I'm getting a bonus later this month and have decided it's about time I bought some flash equipment. I've never used a flash before (other than on-camera) so please bear with me...
I'm considering the 580exII as my main flash. I know it's expensive but it has e-ttl and all that wizardry so if I decide to keep the flash on camera (which I will do occasionally) then it'll be nice to have a semi-auto mode where the flash does some of the hard work for me.
I really want to take the flash off camera so I'm going to try the ebay/cactus triggers. Do I need the 4 or 16 channel version? I assume the 4 channel ones.
My local camera shop have some second-hand flashes in the window for sale. There are some cheap Sigma ones (£29 and £49) which don't instil me with much confidence, but they also have some Nikon flashes: SB24 (£69) and SB28 (£89).
Would the Nikon flashes be a good buy, or should I go for a brand new Vivitar? The secondary flash would probably be used off camera but would it be useful if I used it on camera (eg if I wanted to lend someone my other camera). Finally, will the second flash fire automatically as soon as it detects the first one go off?
Now all I have to do is work out where to buy the light stands, clamps and everything else 
...

