If you go nikon, pick up the AF-S Nikkor 18-200mm 1:3.5-5.6 G ED DX VR Lens.
http://www.kenrockwell.com/nikon/18200.htm
This is the Lens I keep on my camera for everyday shooting. It covers 90% of what your ever going to shoot.
To round out my kit I also have an 8mm fisheye that I use for 360 for panoramic.
http://www.peleng8.com/ (I plan in getting sigmas in the future but the pelengs a fun cheap lens to play with) I also have had the nikon 10.5mm fisheye (sharp and clean but expensive)
For close up work I have a Nikkor 105 Micro lens. I have the version that came out right before the VR option. Wishing I would have the VR option and might sell mine to move to the newer lens at some point.
For shooting events I use to use the 70-200 VR
http://www.kenrockwell.com/nikon/70200vr.htm Very expensive lens but does give you options at 200mm that you just can't do with any other lens due to it's low 2.8f. (I sold mine after a year with it as I just couldn't justify the expense of the lens with how little I actually used it, the 18-200mm took it's place somewhat altho it can't handle as low of light conditions but honestly with a good tripod that becomes less of an issue.
Keep in mind that the Nikon does not use a full frame sensor. (Some of the new ones do) what this means is you have a 1.5x magnification on all your lens. so you 200mm becomes a 300mm etc.
Another lens I think everyone should own is a really fast prime. I have the 50mm 1.4 which on the d2x becomes a 75mm... I also have a Sigma 30mm 1.4. On the d2x the 30mm becomes a 45mm so very close to the 50mm your looking for for 1:1 photography. Also have the 1.4f means your able to shoot in some very low light conditions.
I have other lens I keep in my bag that do nothing but gather dust at this point. The ones I've listed are the ones I found I use on a regular bases for my type of shooting. I do a lot of commercial shooting for products and business locations that are used for mainstream websites and with the kit above have not ran into anything I couldn't shoot.