You want convenience, so go with the 18-200. The 18-105 that came with your camera and the 70-300VR are both better lens than the 18-200(with the 70-300VR being much better optically and with focusing speed), but they won't give you the convenience that your looking for. None of the lenses will be very good for close up/macro photography but this also depends on your expectations, which vary from person to person.
I just recently received a D90 from my husband, and it's my first SLR. It came as a kit with a lens, but the zoom feature isn't that great. I'd like to have a multi-purpose lens, that works for close-ups and good zoom shots. Both the following lenses have been recommended, but would anyone have any thoughts as to which to buy? I'd like to have the convenience of using a single lens without changing them out for zoom shots, but, beyond that, I don't know which would be best. It seems the 70-300mm is primarily zoom, and I'm probably looking for something like the 18-200mm model, but any advice would be appreciated. Thanks!
AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II
AF-S VR Zoom-Nikkor 70-300mm f/4.5-5.6G IF-ED (4.3x)