Ultrabook or Surface?

So, here's my personal situation:

I have an ASUS G73 with windows 7 as my pain PC.... it's a laptop, but it's such a beast I won't even take it anywhere. Since CES 2012 I've been in love with the Ideapad Yoga.... a good looking ultrabook that flips into a tablet, although really I'm most enthused about the stand mode for sitting in bed and having a screen nice and close. I am, however, also pining to get my hands on a surface. I only really need basic apps to be mobile with me (Office, etc.) so the surface RT actually could fill the void and I could just leave my G73 at home.

So what do you think? Get the Surface RT and use it until my G73 dies and hopefully the yoga is reduced in price? Or just deplete the bank reserves and get both? See the other thing is I already have a Nexus 7 which I love, so at this point, a 13" is more needed than a 10"