Personal reasons for upgrading to 7 in order of importance: 64-bit memory space support (crucial, considering enormous browser bloat after the FF 3.5 era) TRI

Personal reasons for upgrading to 7 in order of importance: 64-bit memory space support (crucial, considering enormous browser bloat after the FF 3.5 era) TRIM support for SSDs (I switched to 7 when consumer SSDs started to become affordable) DX11+ for gaming (DX10 was a wash in Vista, but by the time I switched to 7, there were some games that actually did look noticeably better with DX11) Half-Open connection fix for torrenting. But I'm a power user, so reasons for regular users may vary.