You can cut off titanium rings. You can't cut off tungsten or tungsten carbide, but it's actually even easier: it's extremely brittle, so it'll fatigue and crack with a pair of pliers VERY quickly and easily.

My ring is tungsten carbide, my wife's as well. Just as shiny/pretty as most other metals, but almost indestructible (unless you crack it with pliers, of course). No scratches on it, it's still just as shiny as the day I put it on the first time.

As far as resizing, get one that includes a free lifetime resizing plan. The cheaper online brands may not have it, but our tungsten carbide bands came with a lifetime warranty and free lifetime resizing. Of couse the ring itself can't be changed, but you just mail the rink back to them and they mail a new one of a different size back to you. I think it was like $20 shipping/handling to resize my wife's ring.