It doesn't look like a fair comparison was made. Let's compare them in detail, configured as equivalently as possible.
Dell Precision M6300:
Intel? Core? 2 Duo T9300 (2.50GHz, 6M L2 Cache, 800MHz) Dual Core
Genuine Windows Vista? Ultimate Service Pack 1, With media
Productivity software: none
3 Year Basic Limited Warranty and 3 Year NBD On-Site Service
NVIDIA? Quadro FX 1600M 512MB TurboCache (256MB discrete)
17 inch Wide Screen WUXGA TrueLife LCD Panel
Touchpad AND UPEK? Fingerprint Reader
4.0GB, DDR2-667 SDRAM, 2 DIMMS
250GB Hard Drive, 9.5MM, 7200RPM (Free Fall Sensor)
8X DVD+/-RW w/Roxio Creator? and Cyberlink PDVD?
Intel? 4965 802.11a/g/n Dual-Band Mini Card
Dell Wireless? 360 Bluetooth Module for Vista
Resource DVD - Contains Diagnostics and Drivers
Total: $1,990
HP HDX18t:
Windows Vista Ultimate with Service Pack 1 (64-bit)
Intel Core 2 Duo Processor T9400 (2.53 GHz)
18.4" diagonal High Definition HP Ultra BrightView Infinity Display (1920x1080p)
4GB DDR2 System Memory (2 Dimm)
512MB NVIDIA GeForce 9600M GT
250GB 7200RPM SATA Hard Drive with HP ProtectSmart Hard Drive Protection
Webcam + Fingerprint Reader with HP Imprint Finish (Fluid)
Intel Next-Gen Wireless-N Mini-card with Bluetooth
Blu-Ray ROM with SuperMulti DVD+/-R/RW Double Layer
No TV Tuner
8 Cell Lithium Ion Battery
No Productivity Software
Roxio Creator 2009
3-year HP Pick Up and Return
Total: $2,127.98
(Note that I added the option for the higher resolution screen and the fingerprint reader to the Dell, in order to make a fair price comparison. For the same reason, I added a 3 year warranty, Roxio Creator software, and bluetooth to the HP.)
Configured as equivalently as possible, the HP costs $138 more than the Dell. What does that $138 buy?
The HP comes with a Blu-Ray drive. Advantage: HP
The HP comes with a faster Front Side Bus than the Dell (1066 MHz vs. 800 MHz). Advantage: HP
The HP has a slightly (11.4%) larger screen, by area, but the Dell has slightly (11.1%) more pixels. For laptops, pixel density is more important than screen size, and higher resolution is always better. Advantage: Dell
The HP has 4 USB ports (one used as eSATA) while the Dell has 6 USB ports. Advantage: Dell
The Dell has a phone modem, and the HP has a 5 in on media card reader, neither feature important enough to affect your decision, IMO.
The Dell has a professional oriented video card, while the HP has a gaming oriented card. Both are mid-range in their respective product lines. Advantage: Tie.
As a desktop replacement, I'm inclined to recommend the Dell (of the two), although the faster FSB of the HP does have appeal (much more than the Blu-Ray drive). For a portable entertainment device, the HP wins out, due to the Blu-Ray drive and sufficient resolution to actually support HD, something sorely missing from many laptops with Blu-Ray or HD-DVD drives.