"Just got my 1TB WD Scorpio drive installed in my 1st gen (late 2008) 2.8GHz unibody MacBook Pro. It is a 4k (sector) drive, it has the Advanced Format description on the label. I can get a pic tonight if you want one.
(Reader FYI - the Feb 15, 2010 news page had a post on WD's new 'Advanced Format' drives (4KB sectors vs 512 byte) that also linked to their article about Advanced Format drives (www.wdc.com/en/products/advancedformat/) and Advanced Format Align Utility (www.wdc.com/en/products/advancedformat/) which they note as not required for OS X.)

The drive was easy to put in but it now is flush with the battery due to thickness, the cable was a little tough to put in beside the drive. Had to tuck it in, but it eventually fit.

(As mentioned before, being 12.5mm high it can fit in Unibody MacBook/Pros but for the pre-Unibody MacBook Pros, only the 17in can fit 12.5mm high Hard Drives. And the Mini as far as I know still can't take 12.5mm high HDs.)

I have heard no clicking noises yet. The drive is audible when spinning and reading, but you really have to get your ear close. I migrated from a 640GB WD, and the Aperture trick worked. (ref: a MBP owner's Aperture User's Speedup Tip) Having the Aperture library as one file, not fragmented has really sped things up plus the swap space is not fragmented. One bounce and it is up.

Here is Xbench from nothing but 10.6.2 installed fresh. (Of course every time you run XB, it comes out different.)

Xbench Version 1.3
System Version 10.6.2 (10C540)
Physical RAM 4096 MB
Model MacBookPro5,1

Drive Type WDC WD10TPVT-00HT5T0
Disk Test 54.63 (overall score)
Sequential 104.58
Uncached Write 134.89 - 82.82 MB/sec [4K blocks]
Uncached Write 125.83 - 71.19 MB/sec [256K blocks]
Uncached Read 60.30 - 17.65 MB/sec [4K blocks]
Uncached Read 158.63 - 79.73 MB/sec [256K blocks]
Random 36.97
Uncached Write 13.80 - 1.46 MB/sec [4K blocks]
Uncached Write 121.08 - 38.76 MB/sec [256K blocks]
Uncached Read 54.90 - 0.39 MB/sec [4K blocks]
Uncached Read 108.28 - 20.09 MB/sec [256K blocks]

Here are some more tests using Kona (AJA System Test)

Hope this helps someone. Anything else let me know.
Thanks, Rob"

(added June 25th, 2010)
"I recently put a 1TB drive into my 13" unibody MacBook Pro. Here are my issues of note:

* Bottom case isn't quite snug on the right side - I'm a little worried that any impact (i.e. dropping it to the desk) would be transferred through to the drive casing.
(I'm not sure this is the same thing - but on my early 09 MBP 17in, after twice removing the bottom cover for HD swaps I noticed (both times) that I could feel some movement (and slight chirp/noise) by pressing around the center of the bottom cover. I seemed to have solved that by loosening all screws a bit and then pressing down a bit with the palm of one hand while tightening the screws down again.)

* I was getting frequent clicks due to the head unloading issue. First I tried disabling drive sleep in the power preferences, then disabling the SMS with pmset, but I was still getting clicks every 20 seconds or so when sitting on the couch. I finally tried using hdparm to set the drive to max performance, which resolved the issue. The only side effect I've noted so far is that the drive remains spinning for a few seconds longer after putting the computer to sleep.

* Drive scores 53.57 overall in Xbench.
-Brodie"

There were some Problem reports since the Mid-2009 MacBook Pros/EFI firmware update 1.7 was released, for example a very long Apple forum thread on the subject (no longer online). Some posts in that thread mentioned replacing the SATA cable, forcing SATA I mode, etc. but none of those seems to have been a universal fix for everyone affected.