1280 × 800 vs 1920 × 1080
WXGA 16:10 against Full HD 1080p, side by side.
1920×1080 renders 1,049,600 more pixels than 1280×800 — 102% more. They differ in shape too: 1280×800 is 16:10 while 1920×1080 is 16:9, so windows and video fit differently.
Mostly a projector question these days. WXGA projectors are noticeably cheaper, and at presentation distance with slides the 1280×800 grid is acceptable; for movies, sports, or anything with fine text, Full HD is the visible upgrade and the price gap keeps shrinking. On laptops the comparison is settled history — 1280×800 hasn't shipped in years.