The ones that YOU shoot the best, are reliable, you have confidence in, and can afford!
The most important thing is that you try several that you select from makes, and models you like. Don't befooled by price either. Mane top of the line, high end guns aren't anything sugnificantly better than less costly name brand guns.
If you are looking for a list of suggestions for you to consider, I have to agree with the above advice.
If you are looking for a for fun thread with a list of everyone's favorite guns in different calibers, here is mine based on guns I've owned or friend's guns, rentals and others I've shot on multiple occasions:
9mm:
Depends upon if you are talking full sized service guns or compact micro-9s. For the full-sized gun, the CZ 75B hands down. For the micro-9mm, it is between my SIG P290RS and a buddy's Kahr PM9.
.40S&W:
I was stupid to sell my SIG P229 a few years back. If they weren't so darned expensive, or if I wasn't on a teacher's salary, I'd have replaced it long ago.
.45ACP:
I love the 1911 platform. Feels good in my hands, points naturally, and is very accurate. Though, for some reason, the SIG P220 Carry or Combat has been high on my want list for a few years now.
10mm:
I don't have one, and I've never shot one. I wouldn't mind a 1911 for the range. If I was going to get one for self defense, it would be one of the Glocks. I love SIG, and SIG is putting the P220 out in 10mm, so that may win out if I ever actually buy a 10mm (doubtful).