I spend a fair amount of time surfing for game-related stuff. Beyond Google, I've found the following to be consistently useful:

• GameFaqs
• Killer List of Videogames
• The Video Game Museum
• Wikipedia
• Gamespot
• Insert Credit
• Penny Arcade

More specifically useful:

• System 16: The Arcade Museum - arcade hardware
• Sega Mark-III (Japanese)
• NEC PC-FX
• PCEngine Catalog Project
• X68000
• The Howard & Nester Comics Archive
• King's Field
• 2010 Street Fighter (Japanese)
• Translated Memories - Silent Hill
• Satoworks - Takayoshi Sato, graphics man behind Silent Hill and Silent Hill 2
• Speed Demos Archive
• Twin Galaxies - game world records
• Metacritic- consolidated game reivews
• Chudah's Corner - game soundtracks
• SNESMusic- SPC files
• DeJap - SNES fan translations
• Jchensor - Fighting game aficionado