[HAVOC]

If you're not concerned about price, but performance and capacity, why not a 100GB 7200rpm drive from Seagate or Hitachi or the 160GB 5400rpm from Seagate. Higher density for a given platter size/rotational speed generally gives better throughput.

http://www.laptoplogic.com/reviews/detail.php?id=104&part=full has a good review of the pertinent models.

 

[HAVOC]

Whether or not you'll notice a difference is entirely dependent on what you're doing and what sort of differences you can perceive. In general, I'd be more worried about capacity that performance, unless you're doing some very disk-intensive work. Database work, web serving, super enormous calculations that can't fit in RAM (you do have enough RAM, right..?) and that sort of thing can make disk performance an issue, but otherwise it's minor for the most part.

 

[HAVOC]

Some of the really huge cases (the 12 pounders) have 2 bays, but most do not.

What's the cost difference they want for the bigger drives? Compare that to what it would cost to buy one on the open market.

I would plan on reloading the thing from scratch anyway. Most OEM type PC come loaded with so much crap that they run like dogs til you blow it all out. And starting over is often faster than trying to dig it all out.

In days past however, HP didn't send a real OS disc, just their horrid image software that helpfully installs (without any choice from you) all the crap you didn't want in the first place.

On a personal note, I wouldn't own an HP if you gave it to me.

If you really want to work within their options, I'd take the 120GB if the premium isn't TOO extreme.