I upgraded my MacBook Pro (MBP) today with a 250GB 5400RPM hard disk from MCE Tech (product info here). The drive came with an external enclosure with USB and eSATA interfaces for the drive I was removing, which is a nice touch, and even so MCE's price was competitive.
I've bought drives from MCE before. They make some good products, and their customer service is excellent. MCE promised the drive would ship in 7 to 10 business days because they were waiting on the enclosures. It shipped on the 10th day, and MCE volunteered to upgrade the order to overnight shipping because of the "delay."
Before installing the new drive, I backed up the old HD to a separate FireWire drive using my Power Mac G5. Apple's machines can be booted into something called "FireWire Target Disk Mode" which makes them act like a self-powered FireWire hard disk; this feature makes backups and upgrades a lot easier.
The new drive came with the tools to perform the upgrade-- though I actually used my own. The instructions were provided in PDF format on CD-ROM, although it seems to me that printed copies would have been cheaper and better.
The upgrade process went smoothly. My MacBook Pro matched the one MCE used to generate the instructions. It was a lot easier to open than my previous PowerBook, which had latches hidden inside the DVD loading slot!
With the new drive installed and the machine back together, I hooked the MBP back up to the G5, partitioned the drive with a 212GB main partition and 20GB of free space for a Vista Boot Camp partition to be added later, then restored the backup to the main partition. The old drive went into the external enclosure, and it's working fine.
The machine booted right up and I'm using it now. The new drive is utterly silent and seems to be at least as fast as the old 160GB Hitachi drive it replaced. The specs imply it should consume a little less power, too. So all in all, it's been a good day!