Like many others, I'd say the Glock 17 or 19 are good STARTING POINTS. They are not, however, God's gift to the gun community, as there are many superior (in my opinion) options in the same class. And yes, I myself, do own a Glock 19, though I don't shoot it often nor do I ever carry it.
That said, for striker guns, here's my picks with some brief explanations including some pros and cons:
HK VP9 with night sights - Ergonomics beat out anything else in class with the interchangeable back straps and side panels. The trigger beats the snot out of the Glock trigger. It's got smoother take up, a nice crisp break and a nice positive reset. If you get the night sight flavor of the VP9, you get three 15 round mags rather than two, and the night sights are excellent Meprolight Tru Dots. The gun is fully ambidexterous without modification to any parts of the gun. Simple manual of arms. The possible downsides, it is a little bit big for concealed carry. I'd say it's closer in size to a Glock 17. Being the size of a Glock 17, I'd have liked to see slightly higher magazine capacity. If you're unfamiliar with them, the paddle magazine release can take a little getting used to or you may just flat out dislike it all together. Biggest downside to the HK VP9, mags are quite pricey and your only option is HK OE mags as there are no aftermarket options available from the likes of Mec Gar, etc.
Walther PPQ - Excellent ergonomics that are second only to the VP9. Slightly smaller footprint than the VP9 making it a more viable carry option. Trigger that equals the VP9 in every way. Like the VP9, it's fully ambidexterous out of the box in the Classic configuration and on the M2 has a reversible push button magazine release. Some little niggles with the PPQ, mags can be a little pricey as with the HK. In standard configuration, the gun has polymer sights, and I can say from experience with my P99, that Kydex holsters can do a number on the front sight. There isn't a great deal of accessories availability for the PPQ, though it is improving at a fast rate.
Smith & Wesson M&P 2.0 - I don't have any trigger time with these, but they do seem to correct a couple of the little gripes I had with the original M&P, particularly the slightly sub par trigger. The new grip texture is excellent and the ergonomics of the gun are in my opinion leaps and bounds ahead of the Glock offerings. Downsides, the full size M&P is a little big for concealed carry as it is the same size as a Glock 17. You have to really be careful when buying one of these as there are quite a number of them out there with a magazine disconnect safety (i.e. gun won't fire with a round chambered, but no magazine inserted).
Springfield XDM - Excellent reliability and accuracy, Superb magazine capacity at 19 rounds in the full size gun. Triggers are very good. Ergonomics are better than Glock, but not quite Walther or HK VP9 good. Downsides, VERY big for concealed carry; it's a little bit of a fat kid in that department. I find the grip safety to be a slightly hokey and unnecessary feature. Can't stand the raised loaded chamber indicator as I've had it catch on the holster when re-holstering (this is on my XD Sub Compact that I had a while back)
Walther P99AS - Excellent ergonomics, like the PPQ. Innovative striker fire system that is true DA/SA with what is essentially a two stage single action trigger, therefore you can safely carry it in SA. Good size for concealed carry as it's only marginally larger than a Glock 19 with a magazine inserted. Very good trigger in both DA and SA. Smooth travel through the take up and a nice crisp break with a positive reset. Downsides. Accessories are essentially non-existent for the P99. You'll be deeply disappointed if you plan to mount anything on the rail as the trigger guard profile prevents you from being able to get the accessory far enough back to line up with the rail notch (mine won't take a Surefire X200 or Streamlight TLR1). If you're averse to them, they are only available with a paddle release. Their grip texture flat out sucks when you're hands are wet or sweaty. All that said, I absolutely adore my P99 and frequently carry it.
Sig Sauer P320 - Good ergonomics. Good trigger. Modular design allows you to buy one gun then get size or caliber conversions without having to fill out another 4473 form and have a background check performed. The advantage to this is really for folks that live in the not so gun friendly states as exchanging sizes and calibers can be quite pricey. Excellent factory night sights. Downsides, though the P320 compact or subcompact are good sizes for carry, if you're planning to carry them IWB, they are a little on the chunky side. With the Army recently adopting a modified version of the P320, availability may or may not be affected. We shall see.
Hammer fired guns:
HK P2000 - Great size for concealed carry (approximately the same size as a Glock 19) and good ergonomics. Excellent accuracy and reliability. Excellent factory night sight option with a third magazine included. Downsides, the DA/SA trigger is pretty meh and the common V2 LEM is also rather lackluster. If one can be found with a V1 Light LEM trigger, get it and don't look back. Magazine release paddles are a little tiny and can be a little tougher to manipulate when wearing gloves, though I'm sure you can swap the paddle on the P2000 for a larger option like that found on the P30 or VP9. Magazine capacity is definitely on the low side for a gun its size at 13 rounds compared to the more common 15 rounds for this size class. And again, since it's an HK, prepare to pay a steep price for magazines.
Sig Sauer SP2022 - What's there to say, it's basically a polymer framed P229. Good magazine capacity, decent to very good trigger depending on whether it has an SRT kit. Very inexpensive. Good size for concealed carry. Excellent Sig night sights from the factory. Downsides, the only real complaint that I have about these is that they use the stupid raised loaded chamber indicator on the top of the slide, and like with the XD and XDM, it can snag
