I highly recommend the P220 line (and P226). They are rock solid reliable and accurate out of the box. There are enough different versions available to suit many tastes/requirements. I also have heard good things about the P229 but a few others didn't like it. I own P220's and one P226 in 40. The P220 line is exclusively .45acp (unless you get a .22lr conversion kit). The P226 can come in .40s&w, .357sig, 9mm. I wish they made a 10mm version.
Here are some pics of mine:
Stainless Elite & Equinox P220's
Stainless Elite 8rnd & 10rnd mags
I love the stainless elite. While I like the regular DA/SA trigger I really like the Short Reset Trigger (SRT) that come with the elite line. They also come with night sites.
Another Sig gun is the P238 in .380acp which gets all great reviews but only if you want a .380. Any gun with you is better than a gun left at home but I prefer 45acp hence my name.
The Sig P250 was interesting but I decided to stay away from it. It has a long trigger DAO. Some like it and others don't. Basically if you go with Sig you won't be disappointed and it should retain most of its value if you decide to sell it. I recommend shooting whatever you are interested before buying (rent at range).
As far as calibers my username gives away my bias. I own one P226 in 40s&w. 40s&w is a snappy round for recoil. I believe it is harder to control than a 45acp, not much but noticeable. The only reason I picked up a used P226 in 40s&w was the ammo shortage when there was no 45acp on the shelf but boxes of 40s&w. I figured if .45acp was good enough for my Dad in WWII it was good enough for me.
The only advantage of 40 over 45 is capacity. My P226 has 13 round magazines where my P220 has 8rnd and a 10rnd but the 10rnd would be awkward to carry other than as a spare. (see above pic). I would suggest shooting both calibers and see what you like better. 40 is a good compromise between the higher normal-capacity 9mm guns and the lower normal-capacity 45's. The secret service and navy seals like the P229 and P226 respectively. ;-)
I did go on a search for a good higher normal capacity 45 and found FN-FNP45 15+1, Para Big Hawg 15+1, then there is Glock, XDm at 13+1.
Good luck with your research and search for your next purchase. :-)