Since this is for home, not carry, size is not a restriction, so here are my OPPINIONS. (i.e.--get what YOU want!)
1)Beretta Elite II 40cal.
The Beretta Elite II is a nice gun, and if you like DA pistols, you can't go wrong with it. Personally, I really like Beretta's, and the Elite is just an improved version. The only thing I don't like is that it has a decocker instead of a safety. I find the safety of the standard models to be very quick to disengage, and have grown to prefer the manual safety on these weapons.
2)Glock 21
This is an excellent gun chambering a very capable cartridge, but it does have a big grip (so does the Beretta) and if you have small hands, it may pose a problem. Also, it doesn't have a manual safety (as you probably know) so the "finger of trigger" rule becomes especially important. (Not that it shouldn't be observed anyway...)
3)Glock 35
Same things as the Glock 21 except a smaller grip, longer barrel, and .40 caliber. Personally, I REALLY like the .40 as a defensive round, and the longer barrel will push those 10mm bullets even harder. The longer sight radius will improve accuracy (how much is debatable)and the gun does have the 3.5 lb. connector (I like!) which is less "fear friendly" but feels better IMO. The 35 also has extended slide/mag releases--Good or bad--You decide. Personally, I like 'em.
4)Sig P226 40cal.
As for the Sig, I love my 239, but I have found that the new Sig Pro's seem to have better trigger pulls than the classics. The decocking lever is MUCH better, however, on the classic line. From what I've heard, and what I've experienced with my 239, Sigs are VERY accurate and dependable. This is also a great gun, but you do have to deal with a DA system, and it has no manual safety. If it fits you bill though, its a great gun.
In short, I think you should buy all four, the trouble is deciding which one to buy first!!!