There sure are a lot of choices out there, but just for now staying in line with what you were shooting, I can say that I have had good luck with the weapons you mentioned.
I have owned Glock pistols, and found them to be a good weapon.
I have owned, and still currently own a Sig Sauer pistol, and find it to be a good weapon.
I have owned a H&K USP 40, and found it to be a good weapon.
So again, as far as quality, you have three good quality brands there.
The tougher choices that will have to be made by you are going to be things like size, weight, caliber/recoil, finish, safety system, magazine capacity, etc.
Some of the more common caliber choices today are the 9mm, .40 S&W, .357 Sig, .45 GAP, .45 ACP.
The 9mm will usually carry 2 to 3 rounds more than the comparable .40 caliber pistol, but the .40 has the oomph advantage. The recoil is not harsh on either caliber (IMO), but the .40 does have noticably more recoil. That bit of extra recoil in the .40 will in turn reimburse you with extra stopping power.
.357 Sig is the marrying of the 9mm bullet to a necked down .40 S&W shell. The advantage this gave to the 9mm bullet was higher velocity, which in turn gives a good bit more muzzle energy than the standard 9mm. I would not feel underpowered with a 9mm, .357 Sig, or a .40 S&W caliber gun, especially if you get good advice when purchasing good ammo for whatever caliber you choose.
I don't have any experience with the .45 Gap, and though I have heard good things, I will not be able to inject an opinion on it.
The .45ACP is nice. A heavy bullet that in my experience gives more of a shove recoil than a kick recoil, but in any case it lets you know you are discharging a weapon
Capacity on the .45 ACP tends to be lower in gun's chambering this round, but again, stopping power is rated pretty damn high (as with any caliber, proper bullet placement and ammo quality has an important role to play here as well).
The recoil is something that one has to get used to on any gun that one purchases, but no matter what caliber one chooses, practice usually takes care of any early on issues that you may experience with any of these calibers I mentioned
Good luck, and welcome to the wonderful world of handgun ownership
Oh, by the way, here are the meanings of some of what follows after certain calibers:
ACP= Automatic Colt Pistol (first being designed for and chambered for a Colt model pistol)
S&W= Smith & Wesson (first being designed for and chambered in a Smith and Wesson pistol)
Sig= Sig/Sig Sauer (first being designed for and chambered in a Sig pistol)
GAP= Glock Automatic Pistol (first being designed for and chambered in a Glock Pistol)