You are barking up my tree since I love 45acp! (hey that rhymes)
I have a few favorite 45's. First you have to decide things like size that fits your hand and capacity.
Sig P220 Stainless Elite - This is my prettiest gun and a great shooting one. Both in accuracy and comfort. I could shoot this one all day. The only drawbacks are price (about $1k includes night sites and short reset trigger) and capacity 8+1. The regular P220's have a polymer frame which makes the gun lighter but also increases felt recoil. I have gotten other P220 models between $800-$900.
H&K USP - This is my favorite gun to carry every day. It has a 12+1 capacity so it holds more than the Sig. It is accurate and mostly comfortable to shoot. Price range is between $7-800 bucks without night sights. I don't have night sights but would prefer them. That would bump the price up around $900. The HK45 is newer and has a few advantages over the USP like standard Picatinny rail, mag release and shaped grip but the USP is 12+1 where the HK45 is only 10+1. Since the HK45 came out the USP prices dropped. The HK45 will run you and extra $1-200.
other - I have two hi capacity 45acp guns that I like but need time to decide if I love them. The first is Para's Big Hawg. If you like 1911's and have average to large hands this is a good gun. My reservation with it is that it needed over 300 rounds to break in and is finicky on some sorts of ammo. It is 14/15+1 depending on the mag you get. The second is the FNH FNP-45. This gun is like a cross between a P220 and a USP and is also 14//15+1 in capacity. Finding a holster for it is more difficult (no serpa) but it seems to shoot very well and is comfortable. The price on these guns is definitely reasonable at around $600. The Big Hawg runs around $800.
BUG - I have a Taurus PT145 Millenium Pro which I love as a BUG. I have a Don Hume pocket holster for it and carry it almost everywhere I go. Having a BUG that uses the same ammo as my primary is a plus and it fits in my pocket.
I have heard good things about the S&W MP line so I don't think you can go wrong there. The only thing I didn't like about it was the 10+1 limit.