With waifus I suppose you're only asking about female characters, right? A bit of a bummer. Well, here's my list:
I'll start things off with Akane from Rewrite. I love her ideals and her personality is very pleasing.
As I'm sure you all know, the only thing I look to in romantic relationships is getting some sort of benefit. This can be anything from a suitable cause to defend to a good servant. While Akane would serve to give me a cause (and tons of moneys) I'm forced to pick Moran from Shikkoku no Sharnoth as the servant type. I can hardly think of a character that's more useful, and she's quite cute.
To the third, huh... So I've got myself a very influential and pleasant person and a hypercompetent robot girl. Seeing as how I already have what I want, the third spot will be all about... Well, stress relief. I love teasing people, and her ninja roleplay earned a spot in my heart- more than anything, she's cute. I'll pick Akatsuki from Log Horizon.