If you are seriously looking for a flash then the F58 is the one to get. Once you get this it will end all your flash lusting. It is NOT expensive at all. You can get it around Rm11xx street price and it is much more affordable than the C and N counterparts. Third party brands is cheaper but don't give you full features, like don't have ADI or don't support wireless etc. Most importantly no other flashes gives you the 'cobra' action!! You just have to experience it to know how good it is.
As for comments on A100 users feeling frustrated and jumping ship - I am an A100 user and one of the early Alpha adopters. I don't feel deprived at all. There are way more lenses from Sony than I can ever find use for. So what if C and N brands have more lenses. It's not like I will use all of them. People just like to say things like that but they themselves really have no use for the so called lenses.

I don't do macro so macro lenses are not for me no matter how sharp or how good the macro capabilities are. I have no need for a 300mm f2.8 lens so it's existence do not add anything to my photography experience. Big, heavy zoom lenses are falling out of favor with me so lenses like the 16-35 and the 24-70 and the 70-200G f2.8 are not very appealing to me. So what does that leave me with - a 50mm prime and I am lusting after the 24mm Zeiss but currently that place is filled by a 20mm prime and I am using a friend's Minolta 24-85mm normal zoom which is just nice. Not too big and heavy. These 3 lenses are enough for me. I might want the newly announced 85mm SAM prime but that depends a lot on the price.

So how many lenses do you really NEED? Do you really have to have every lens in a brand's stable to be able to enjoy your photography? If you have more than 5 lenses you're probably more of a lens collector than a photography enthusiast. Take more pics. Not buy more lenses. A photographer knows how to use the gears he/she has to get the pics he/she wants.