Well I finally got my Toshiba P100-429 notebook refunded and purchased one of these - brilliant decision. The only downside is the dv9000 series gets VERY hot underneath, I've investigated my model and found it was due to the hard disk (a Western Digital), the graphics chip (no heatsink or anything on it) and the RAM hosted slightly below it. The design also means that if you use it on your lap, you block the vents meant to cool these components.
UPDATES I updated this page after my notebook went into repair in July due to a known heat nvidia/amd combo design fault with HP notebooks.
Here's a top 10 list of things to help cool that mega hot HP notebook (and may be applicable for other notebooks).
1. If you have Windows Vista use ReadyBoost. I purchased a £5 1GB DaneElec "High Speed" SD card and have it permanently in the SD card slot just for ReadyBoost. This reduces swap file usage on the hard disk, thus reduces heat it would generate from using it.
2. If you have a Geforce GO GPU inside and Windows Vista, get hold of the latest Nvidia drivers to use the "Powermizer" functionality to slow the graphics processor down when it isn't in use.
3. Power save options. In Vista you have the (advanced) option to power down your hard disk. Set this to 1 minute - whilst you're browsing and not doing much the hard disk can power down. Some people may say this increases hard disk wear. Personally I think that the greater risk comes from melting the hard disk with the excessive heat it can generate.
4. Depending on your OS you may want to install some utilities to help regulate the CPU and CPU efficency. For the AMD Turion X2 I use the dual core optimizer patch, for other OS and AMD processors you could also use the PowerNow utility. See this page for more info on AMD processors. Similar software should also be available for Intel processors.
5. This one is a bit risky but if you're a bit of a techy and confident with replacing user serviceable parts, open up the RAM bay (on my model I also had to open the battery bay to release a lid catch for the RAM bay). Take out the RAM sticks carefully - ensuring you don't blow them with static - and remove the HP stickers. These additional stickers should be easy to remove and just state on them something like "Only replace with part.....".
UPDATE 1:The RAM warranty stickers also went, although I was very careful not to touch the electronics.
UPDATE 2: Between the wifi card and mainboard is usually a strip of insulating tape so the two sets of electronics don't touch - despite the fact they are being separated by a screw mounts (i.e. about 5mm height). The same goes for between the RAM and mainboard. I've removed these as well.
6. If you've done step 5 you may notice something I found rather stupid about the notebook design - the underneath lids' vents have a type of mesh/gauze across them on the inside. I suspect this may act like insulation and can probably be removed, to help airflow through the vents. The gauze may be there to prevent foreign bodies getting into the vents and case. So while this tip may give you big cooling gain, it is also carries risk of the aforementioned and invalidating your warranty.
UPDATE: The gauze simply peels off, and given the CPU fan area doesn't have one I don't think I'll be needing it (and I don't want my notebook to die again).
7. This is an A grade fudge of a tip - if you must use you laptop on your lap, don't cover the vents for long. I find the heat mostly is under the touchpad, where the vents are, but the CPU(?) fan is at the rear left. This fan is also responsible for air flow through the case - so I balance the notebook on my left leg with the left side drive bay vents clear and the rear left fan vent clear, and occasionally move the notebook around so the RAM/GPU vents get air. YMMV.
8. If you use the laptop on a desk, in the case of HP laptops prop the back of it up an inch or so with a thin book to help the airflow.
9. Purchase a laptop/notebook (I use these words interchangeably!) cooler. These are cheap devices that sit between your desk/lap and notebook, and contain air channels and vents and usually have fans that are powered from your notebook USB port. From personal experience the Coolermaster Notepal perfectly complements 17inch DV9xxx HP notebooks for colour and size.
10. If you're not using the notebook - turn it off/make it sleep! This will save wear and tear.