If you're looking for a polymer pistol, look for Glock, Springfield XD or S&W M&P. They're all very reliable and (despite fanboyism for one brand or another) rather similar.
If you're looking for steel, I'd go with SIG, Beretta or a CZ-75b.
Personally, I like the XD's grip angle and feel better than Glock. I like the M&P's feel, but not its trigger. Truth be told, none of the polymer pistols have good triggers out of the box. Glock is going to have the best aftermarket support, followed by XD, followed by M&P. On the metal side, SIG is probably the most solid choice, but I've had GREAT results with the CZ-75b's that my friends own.
You mentioned capacity of ~30... most 30 round aftermarket magazines for pistols are prone to jamming. They are toys, and not much more.
For stock capacity, the Springfield XDm in 9mm comes with 19 round magazines, the S&W M&P9 and Glock 17 both come with 17 rounders. SIG 226s usually come with 15 round magazines, Berettas usually come with 15/16 rounders, CZ-75b will be 16 or 18 depending on model. Some aftermarket manufacturers make reliable magazines that hold 1-2 more rounds than factory. Almost all have the ability to have an extended base-plate added that increases capacity by 3-5 rounds. That is about the limit to reliable feeding in a pistol.
If I was gunning for solely capacity, I would get an XDm and throw
http://www.PistolGear.com aluminum base-plate extensions on for a capacity of 28+1. That's about as high as you'll get with reliability intact. But you'll be paying ~$100 per magazine with those base-plate extenders.
EDIT: never mind about Pistol Gear's metal XDm magazine extenders seems they're out of them. Best bet then would be Arredondo's which would give you 23+1.
