Hate to say it Will, but that Gateway sucks.
You should compare the portability (size/weight), as well as video and screen options.
This ASUS is outstanding for $1288: ASUS A8 Series A8JP-4S029M
Display: 14" WXGA+ 1440x900 (better)
Processor: Core 2 Duo T7200 (The same 2GHz, 4MB L2 cache)
RAM: 1GB DDR2 667 (same, but the VRAM makes it better)
Hard Drive: 120GB 5400RPM SATA (better) (another $150 if from Apple)
Optical: 8x DVD burner (better)
Wireless: 802.11abg/Bluetooth/IRDA (IRDA better)
LAN: 10/100/1000 (same)
Video: Dedicated Mobility X1700 with its own 256MB (Better than the MBPro)
Video out: DVI, VGA, S-Video (way better)
Cards: MMC, SD, MS, MS PRO, and an ExpressCard 54 slot (all better)
Other: 5xUSB, 1x1394a, 1xheadphone, 1xmicrophone (+4 USB better)
Webcam: yes, but crappy (worse)
Weight: 5.25lbs (same)
Warranty: 2yr parts & labor (+1yr)
Other: Carrying case, mouse, junk. (all better)
OS: Media Center (free Vista upgrade) (different)
The only place the MacBook does better is the pre-N wireless, better webcam, and style. The MacBook's slightly smaller size may be better or worse.
Oh, and the ASUS has user upgradeable everything. Everything that's available anyway: RAM, HD, video, wireless, even the CPU.