What do you love/not-love about your laptop... have you seen any awesome pre-fin-year sales on these laptops?
I use a 13" MacBook Air and I *love* it's battery life, light weight, and robust construction. I travel a lot, and when a carry-on bag is limited to 7kg every gram counts. When I'm at my desk, I have it hooked up to a 24" external screen, position it on a stand, and use a wireless Apple keyboard plus a wireless Logitech mouse to have essentially a dual-screen desktop configuration.
Irrespective of which brand of notebook you purchase, I'd definitely recommend you invest in an SSD (Solid State Drive) - they're so ridiculously faster than a traditional Hard Disk Drive (HDD) that it'll blow you away. You might think it's just one small part of the equation, but you'd be wrong - the specs of my Macbook Air are nothing special (1.8GHz i5 with 4GB RAM) but due to the blazing fast SSD this machine has handled everything I've thrown at it including Adobe InDesign, Photoshop, Illustrator, Dreamweaver, Aperture, Microsoft Office suite, Dropbox, Google Drive, and scores of apps/windows active simultaneously - with a HDD you'd need to double all the other specs to make that possible. I can't recommend SSD highly enough.
I love connecting mine into a good old fashioned docking station with all your plugs and screens connected and ready to go. This gives you the best of both worlds, full desktop experience and fully mobile on same machine when removed from dock.