Hai everybody... I need advice /recommendation b4 buying a new lens. I'm using Canon EOS400 + Kits lens and Sigma DC 18-200 MM F3.5-6.3 (2nd hand). I'm eyeing on few range of lens from canon model. Going for more on snapshot on people,street n candids.

Zoom Lens
1. EF 28-200mm F3.5-5.6 USM (Is it equivalent with the sigma lens that i have ?)
2. EF 70-300mm F4-5.6 IS USM
3.EF 75-300mm F4-4.6 111 USM

EF-S lens
1.EF-S 18-200mm F3.5-5.6 IS (Is it equivalent with the sigma lens that i have ?)

So,which lens should i go for???
Must make a fast move as my sayang are going to buy for me as a b'day present b4 she change her mind....

Thanx in advance