Something you really need to keep in mind is that for as cheap as it is to "create" photos (essentially free other than the cost of gear) the gear to do it creatively is anything BUT cheap... I've got a pretty serious hobbiest kit, and i'm well over 10 thousand dollars into it.
I would like to strongly disagree. While there are indeed many people who spend obscene amounts of money on photo gear - those are gearheads and geeks, not photographers. Professional photographers may also have expensive kits, but they don't count because they actually earn money with their equipment and each piece they own serves a purpose - they will not buy something unless it pays for itself and fast.
Like another poster above I would second an advice to get a 35mm fast prime, but it would only make sense if you did not already have a zoom lens that covers the same length and a 50mm which is somewhat close to it as well.
To be really honest, I'd say stick with what you have. Is there something you specifically feel is missing with your existing kit? If you just started doing photography, chances are you have not reached the limits of your lenses. The limits you have right now are likely not in your equipment, but in your mind. You need to learn how to best use what you already got, you need to learn how to see things with your eyes the way a camera will see it, you need to study your surroundings to find out when and how to best photograph them. That's a lot of work, and additional gear is just a distraction at this point.
Instead of spending more money on gear, go for a trip somewhere interesting - a change of scenery can do wonders to your pictures!
tzetsin, I'm not trying to sh!t on your parade and your expensive kit, but it's unfair to make others feel like they cannot take creative photographs unless they spend 10K on gear.
