Ball vs fluid head tripods

Hey folks

I'm about to buy a Canon 550D, my first DSLR (though I've been shooting film and video for years) and I'm looking to buy a tripod to go along with it.

I've read quite a few threads on tripods on here, but haven't found one which specifically debates ball versus fluid heads, so I'd be keen to hear your thoughts on that - and recommendations for lightweight choices with whichever head you think is best.

I'm not able to spend $1000 on something really high-end - I'd much rather be going for the $300 range, give or take $100 - if this is possible.

Thanks

Jonathan