I own several Hi-Powers and carry a Hi-Power; but I'd probably recommend the Glock 19. I have around 7k-8k through Glock pistols and another 30k+ through Hi-Powers, so I am familiar with both pistols.
Contrary to what some have said, modern Hi-Powers feed hollowpoint ammo just fine. The Hi-Power was re-designed with a straight feedramp around 1984. I've never had a misfeed with hollowpoint ammo in several thousand rounds of JHPs with my 1995 Hi-Power.
The Hi-Power has the best ergonomics of the three and is also the slimmest and easiest to conceal. You can get 15rd flush-fitting mags and reliable 17rd mags for $20 (and this is WITH the ban in place). It has a manual safety (if you like that) and a magazine disconnect (which can be easily removed if you don't like it). It can also be had with a very crisp trigger; but unfortunately the reset distance leaves something to be desired in rapid shooting. Besides a long reset, it is also a very soft reset that is difficult to feel.
Having said that, the Glock 19 is more reliable, easier to maintain and will last longer. The trigger is practical and has a great short reset as well a positive easy-to-feel reset conducive to rapid shooting. Downside is that some people (including me) have a real hard time transitioning between Glock triggers and other guns. The Phase 3 malfunctions AR15fan mentioned are either an issue or they aren't. From what I've read, the Glock 19s that don't show the problem in several hundred rounds never do show the problem. The ones that do show the problem, I probably wouldn't trust. Never seen it personally. Aside from that, the only thing that will keep a Glock 9mm from chugging out hundreds of thousands of rounds without a stoppage is hard primers in the ammo. As a striker-fired design, it doesn't deal well with those.
Have little experience with the SIGs; but not a big fan of DA/SA or decockers anyway.