Vegas 6 is hd. You wont find much of anything under 500 that will cut HD, though don't quote me on that
Why cut HD if your deploying for the web? Cut DV and make it easy on yourself.
There are many methods to tag a video. Either using the app itself and a text effect to overlay some text or you can make an image with an alpha channel and put it on a timeline above your footage as an overlay.