Your comparison doesn't include that apples only have 90 day warranties and need to spend upwards of $200 to get it upraded to 3 year. If you're trying to get a base computer which the overwhelming majority want, then maybe you wouldn't really want to double the price to get the camera, and bluetooth, osx, sexy looking 1 " thick design in a rapidly outdated tool. Go to hot deal sites such as fatwallet.com>forums or slickdeals.net and you can get yourself a quality laptop for good prices. Since macs only have a single source, which ensures usually better hardware compatibility control, the prices are a lot higher.
Try some of these out
Lenovo 3000 N100 Notebook PC - 699.98 AR
Intel Core Duo T2250 Processor
1GB memory (2x 512MB PC2-5300 DDRII 667)
120GB 5400rpm (12.7mm SATA) Hard Drive
15.4" VibrantView Display
DVD+/- RW Dual Layer
Genuine Windows® Vista Home Premium
Intel Integrated 950 GMA
1 year warranty
http://www.staples.com/webapp/wcs/stores/servlet/StaplesProductDisplay?ts=1176299810115&errorUrl=zipcode&cm_pla=361116&langId=-1&SID=180895-0-0-0-55hnno&AID=10462997&zipCode=95132&cmArea=SEARCH&ddkey=StaplesBeFree&PID=361116&productId=164774&jspStoreDir=Staples&catalogId=10051&cm_cat=358129&cm_ven=CJ&storeId=10001&cm_ite=Ongoing+-+Staples+Basic&prodCatType=1&ddkey=StaplesZipCodeAdd#desclink
Desktop unit - $479
Athlon 64 X2 Dual-Core 3800+
Genuine Windows XP Home Edition
1GB Dual Channel DDR2 SDRAM at 667MHz- 2DIMMs
160GB Serial ATA Hard Drive (7200RPM) w/DataBurst Cache
16x DVD+/-RW Drive
19 inch E197FP Analog Flat Panel
NVIDIA GeForce 6150 LE Integrated Graphics GPU
Integrated 7.1 Channel Audio
1 Year On-site Economy Plan
Integrated 10/100 Ethernet
* 20 inch E207WFP Widescreen Digital Flat Panel [add $50]
1 year warranty
http://configure.us.dell.com/dellstore/config.aspx?c=us&cs=04&kc=6W300&l=en&oc=bddecbj&s=bsd
Starting this Sunday (04/08/2007)bestbuy will have the A135-s4527 laptop on sale for $599.99
Toshiba Satellite 15.4" Widescreen Notebook PC (A135-S4527)
• Intel Pentium Dual Core T2080
• 120GB hard drive
• Burns DVDs and CDs
• 1GB of DDR2 memory
• Built-in 802.11gb wireless
• Windows Vista Home Premium
I went to dell's site. Dell>Small Business>Inspiron 6400 line. Bigger harddrive. Way better graphics card blue tooth, 9 monthes longer warranty. no icamera though =(. $1,142, $357 (24%) less than 13" macbook
PROCESSOR Intel® Core™ 2 Duo T7200 (2.00GHz, 4MB L2 Cache, 667MHz FSB) edit
OPERATING SYSTEM Genuine Windows® XP Home edit
LCD PANEL 15.4 inch Wide Screen XGA Display edit
MEMORY 1GB Shared Dual Channel DDR2 SDRAM at 533MHz, 2 Dimm edit
HARD DRIVE 120GB 5400rpm SATA Hard Drive edit
OPTICAL DRIVE 8X CD/DVD Burner (DVD+/-RW) with double-layer DVD+R write capability edit
VIDEO CARD 256MB ATI MOBILITY™ RADEON® X1400 HyperMemory™ edit
WI-FI WIRELESS CARD Intel PRO/Wireless 3945 Internal Wireless edit
BLUETOOTH WIRELESS Dell Wireless 355 Bluetooth Internal (2.0 + Enhanced Data Rate) edit
SOUND OPTION Integrated Audio edit
MEDIA DIRECT Media Direct 3.0