My newest infatuation (updated daily it seems) is the Smith & Wesson 5906. Maybe not as concealable as I would like but an awesome weapon from all reports.
The absolute best buys for compact 9mm handguns right now are either the Sig P2022 or the FN Herstal FNP-9. Both can be had for 400-450 dollars. Right now there is a Sig P2022 with night sights at PSS for 459 and Fort Liberty has FNP-9's (and some in 40SW) with 5 total mags (three 10 rounders) for around $400. Both fit your criteria, are concealable with many holster options, and are DA/SA. If you are willing to spend just a little bit more PSS has an M&P9 with manual safety as of last Saturday.
I am a bigger guy so I am usually pretty successful in hiding anything short of a just of a small RPG
I have daily carried a S&W M&P 40 for quite some time now, and was looking for something small and lightweight but still comfortable and that didnt make my pants fall down!
I just picked up for $ 550 at the Valpo Gun show a brand new WALTHER PPS, (Police Pistole Slim) and had the chance this AM to put the first 100 rounds down range. Recoil is quite manageable, (certainly less than the M&P 40) and it is very accurate.
Trigger is a little firm, but very consistent. Little more difficult to get a clean double tap, but that is more my unfamiliarity than anything else, (the M&P which I shoot for IDPA has a modified sear and reset courtesy of APEX Tactical)
In a word, LOVE the PPS...! about a half inch shorter in both the barrel and the grip, but the biggest difference is the WIDTH at almost exactly an inch. SLIM is a good description...
Biggest drawback to it right now is the need for Night sights, but Mepro makes a set for it (which I have on order from Optics Planet for 75 bucks) so that is the next upgrade. It is unbelievably comfortable for IWB carry (A good IWB holster like a Crossbreed or other Kydex type holster is a must.... )
I find I dont even need to tuck in the shirt over the holster, just put out some slack and let the shirt hang over it. (remember tho, Im a big dude). It just hugs up against you.
Finally, dont let the German magazine release scare you off. Their logic actually makes sense as it is nearly impossible to inadvertently hit the mag release on either the draw or in the firing grip, and on a mag change, the index finger simply dropping off the trigger to the bottom of the guard to release the mag is sweet and much faster than relaxing your firing grip...
I am VERY pleased with this purchase and it is now my EDC for sure. It also carries service through S&W in America.... One sweet piece of "German Engineering" in my opinion.
FWIW, YMMV
If I was in the market for a new gun, and it had to be in 9mm... It would be either the new xdm 3.8, or the M&P for edc. If not it would be the new 5.25 xdm, or the M&P pro series.