Just look at the things that cost a bit to replace/fix/add.

Kitchen; bathroom; boiler; double glazing; fuse box [check if it's an old one or the newer twin RCD type like THIS; does it need replastering/skimming [e.g are the ceilings artexed/stippled and you want smooth?]; is any tiling in good condition; are the floors/flooring/carpeting ok; can you see the roof and see if there are any loose tiles; are there any big trees near the house that could have roots under the property etc etc.

We bought the first place we looked at planning on painting it and moving in. So far I've had it entirely replastered and redecorated, put a new bathroom in, new kitchen, new windows and front door, new fuse box, rewired every room, new earth, new carpets and floor in every room... I wish I'd put a post up before we bought but like you I went with the Mrs and we got carried away but at least it's almost exactly how we want it now.