First of all, welcome to OCDO, and congratulations on making the VERY important and serious decision to carry a firearm for self-defense. You're going to find that there are a LOT of very knowledgeable people on this forum, and you'll get a LOT of very good info here. We've got a great group on OCDO...
If you are used to shooting .45LC, you will find that some of the "smaller caliber" semiautos like 9mm, .40S&W and even .380 Auto will seem to b=have a more "brisk" or "snappy" recoil than a .45LC SAR. (I had a polymer .380 auto, a Grendel P-12, that had more "kick" than my stainless steel Colt 1911 Delta Elite 10mm!) That is a perfectly normal perception. A lot of people find that to be the case with the smaller-diameter (but higher-pressure) calibers.
The .45acp would be a good "transition gun" for you, considering your experience, and recoil perceptions. There are a BOATLOAD of good .45acps out there, ranging from very affordable to "if you've got to ask, you can't afford it!"
For the 1911 style, look at Colt (of course!), Para Ordnance, Kimber, Rock Island Armory, and Springfield.
For other .45acp pistol designs, look at Sig (pricey but built like a swiss watch) or Glock (ugly, VERY different from what you are used to , but they are the "pack mule" of the firearms world and will work no matter what you do to them). Springfield Armory makes an XD model in '45acp, and on the budget end of the polymer/non-1911 designs is the HiPoint.
As I'm sure you know from your experience with SARs, you get what you pay for in firearms, and with semiautos that is no different. The pricey firearms tend to have more "sexy" fit and finish, spiffy grips, polished slides, etc. The cheaper guns might not be as "sparkley" but even the "budget" makes are pretty reliable these days.
You're going to get as many opinions as there are members on a question like this, so be prepared for an avalanche of posts.
My suggestion is to get to a shooting range that rents firearms, and just try a bunch of different makes and models out. We can't pick a gun for you--your hand, eyes, muscles, and aesthetics are all YOUR own personal, private specifications, and the only way to get a firearm that:
1) fits your needs,
2) fits your body, and
3) you enjoy shooting,
is to shoot a bunch of different makes and models until you find the one that "just fits"...
Good luck, and keep us updated on your "quest".