Mine does that vague 'thumpy' sound, too, when you go over just the right kind of shallow bumps (from the right front corner). I thought it might be a strut, too, but when I replaced all the struts a few months ago, the sound is still there. (For what it's worth- I replaced with OEM struts. I'm happy with the improvements at 130,xxx mi's.) It's been 'with' the car for quite a while, so I thought I'd just have to live with it. It sounds like some exploration might find a loose bushing or something.

At least I'm not the only one....

-Mark