Owner and user of all three popular OS machines.
Macbook Pro - Video Editing. Uni systems use FCP 7 so I needed one for compatibility. I use it only for video editing. All photography editing is done on PC. Newest macbooks have a nice screen but literally 0 options for upgrades and no non-apple repair options. Fused lid = broken camera? replace the whole damn screen. I like web browsing on it, because that two finger flick page back is sweet.
Windows Laptop - Stills editing, gaming, watching movies (bluray drive), has grazy good GFX card in.
Ubuntu/Mint laptop - travelling. Some movies, ability to store photos, just fine for the necessities.
1k on a windows machine will go so, so much further than 1k in teh apple store.