/Recently converted Macfag reporting in.
I picked up one of the 2012 Mac Book Air's late last year to replace an ageing Dell Ultrabook I had.
It fit in with what I wanted (ie not gaming, and very portable computing)
I wound up going with the Mac coz I'm not dependant on mobile computing, and wanted to give MacOS a go.
I don't regret the decision at all, and in fact once Steam and GOG get a bit more of their libraries setup for Mac's I might make a Hacktel of my desktop...
Battery life on my MBA is ridiculous, but, as you said and has been pointed out you dun wanna Mac.
There's a Dell XPS lappy that is a 'I can't believe it's not a MBA' clone which would be faily similar.
It had a 'dedicated' graphics card (read ATi/nVidia GFX chipset instead of the MBA's i5 'on CPU' GFX option) which would be good, but remember, stuff like that will only drink your battery faster.
(EDIT: as it turns out, it's the one I linked below, and the outgoing model (currently $999)
has the 'intel HD3000' on die GPU and the new model (currently $1299)
has the 'HD4000' on die GPU (not the greatest for gaming, but not crippling like the older integrated intel graphics chipsets). The $300 price difference between those two buys you the 'newer' 'integrated GPU' an extra 4GB of RAM and Windows 8)
I think Skitza's call is a pretty good one (RE: X series stink pad) esp. in terms of 'long battery uptime' whilst using it, but keep an eye on prices... they're pretty painful at full RRP, but go on sale frequently enough to snap one up at a better price.
Other than that the Dell XPS types in more recent years are getting better and better from what I've seen.This is a prime example
I can't speak for the battery life (in terms of charge, and retention of charge) for the Dells; that's why I moved on from my older Dell tho.... the bastard's battery would only last an hour or so off battery itself; but 4 years have passed since then so see how you go.
p.s. keep an eye on the resolution of the screens on the 11-13" range of laptops, my only grievance on the MBA is that the res is poo (11" @ 1366x768, where my old Dell was 12.1 @ 1440x900)
EDIT: Mongie, there's a 'current model' [Read: Windows 8 'ready/equipped'] Dell
I've spotted @ my local JB Hi-Fi which meets those needs. It's a tad on the expensive side currently (like $1700 from memory (Starts at $1500 on the link immediately above)) but worth looking at if you're serious.
Other than that, in the 'laptop/tablets' that are running Windows 8 atm, they're all pretty poo.
All are advertising as 'laptop/tablets' but they'd all make boat anchors of tablets... (the Dell is well over 1kg, which for me, makes it less of a tablet and more of a laptop)