I think Geli's comment is correct. The first question you need to answer is what type of photo's do you want to take, this will guide the type of equipment you will need (rather than 'lust' for
). Suggestions of flash, tripod etc are good - all generally required standard equipment. Lenses, however are generally the most expensive additions, and should be considered in context of what you want to do.
If it's landscape, a good wide angle helps, if it's portrait a good 50mm or 100 mm lens helps. Sports shots then a good fast telephoto (or zoom telephoto). Then you have macro photography where a ring flash could be added, with specific Macro lens and electronic shutter release.
So my ten cents worth is have an idea of what you like taking pictures of and work from there. As many have mentioned, you can quite quickly end up with a very expensive equipment inventory that you don't use very often (Like many of us I'm sure
)