Depends on your budget. I’m asuming you’re thinking of spending under $10K.... so:
For around $3500 I would recommend the Canon XH-A1 (HiDef). Image quality is on par with the much more expensive XL-H1 but the A1 has a fixed lens and no SDI out. It shoots HD on tape (plusses and minuses to that).
In fact all of the JVC and Canon cams shoot HD in Long GOP on tape. This makes it easy to shoot with but can be a pain to edit. You can also record to an external hard drive with any of these cams, but factor in the cost of that hardware.
Around the $6K mark you’ve got the JVC HD-GY110U. Has interchangeble lenses. Shoots nice looking pictures.
If you can afford around $10K:
There’s the upgraded JVC 200 series with SDI out, timecode and a few other extras, but may not be worth the extra $ over the 110.
The Canon XL-H1 shoots quite nice pictures, has interchangable lenses, SDI out.
The HVX200 is a great camera (I have one) with tapeless HD workflow, but you’re looking at close to $10K to build an HD production kit (HD monitor, P2 cards, backup drives).
The new Sony XDCAM EX cams just being released are worth checking out. At around $7K, these cams could burst Panasonic’s P2 bubble.
Best,
Simon.