With the wheel off the ground, grab it and shake it. Is there any play? The hub bearing might be toast. Also stick a couple fingers on the axle u-joint and wiggle it hard. shouldn't be any play there either. Inspect the bushings in you sway bar. they can cause a nasty thump if they are trashed. Although that wouldn't affect the wheel not spinning. Is the brake seized up? Might be you're unlucky and its a combination of things.
2001 XJ Sport
3" Rusty's AAL and Springs
1" Daystar Shackles and (2) 3/4 front spring spacers
1" Transfer Case Drop, Iron Man Adjustable LCA's
RE Adjustable Trac Bar, Rusty's Adjustable UCA's
31" Uniroyal AT