This is what I have so far:
Nikon D50
18-135mm lens
55-200mm lens
70-300mm lens
50mm 1.8 lens
SB600 Flash (although a friend who is a pro says 90% of photos should have NO flash)
My style is all over the place. I have three kids, so there is lots of opportunities, then I like nature, sports and everything in between. So I guess I just need every lens Nikon makes!
AMEN!!
Here are my thoughts. I have a VERY similar set up. D50, 18-70mm lens, 70-300mm VR lens, 50mm f/1.8, 90mm f/2.8, SB-600 (that is used 90% of the time with a Gary Fong Lightsphere II Difuser).
I love the Tamron 90mm f/2.8 macro, it is crazy sharp, the sharpest of my 4 lenses, even sharper than the 50mm f/1.8.
A few lenses I have on my list are a Sigma 24 or 28mm f/1.8. With the digital crop factor the 50mm is like 75mm. So the 24 or 28 would be more like the 50 would be on film. 36 and 42mm respectively.
When my kids get older (have 3 myself) another lens will depend on their activities. The 85mm f/1.8 could come in hand for indoor sports/activities.
While I probably wont get one, the Nikkor 60mm f/2.8 Macro is a great lens. I like the Tamron 90mm f/2.8 better and I got it for a great price used at keh.com. Though Nikkor has a 105mm f/2.8 macro with VR which is veerrrrrry nice.
You might consider getting better zooms like the 70-200mm f/2.8 VR or if thats to much the 80-200mm f/2.8 or Sigma's 70-200mm f/2.8. I also would love to get the Sigma 10-20mm f/3.5-4.5. If your into birding or things that need really long reach Sigma has a 50-500mm.
My next lens is going to be an upgrade in zoom length. I'm going to dump my 18-70 and get either the 18-135 or if I can save enough money the 18-200 VR. I like the idea of having VR for those times when I don't have a tripod but need the longer exposure.
There really is almost to many lenses to go through. You'll have to see where your eye, camera and budget take you for the next step. Though it seems as though a nice macro lens might a good option as it can be used in nature and for sports because of the 90mm being croped to 135mm at f/2.8 or the 105 croped to 157mm at f/2.8.