It's hardly contained in a nice, tidy trade paperback (or even a series of them), but I think you would enjoy the first decade or so of post-Crisis stories. It presents a more "down to earth" Superman, but still captures the ideals and imagination and other things that make Superman great.

Unfortunately, trade paperbacks of this era are far from complete. And, given the criteria you laid out, the stories that might be most appealing to you are, for the most part, not collected.

"Krisis on the Krimson Kryptonite" from this era is collected, you might enjoy that. "Panic in the Sky" is great, but more "summer blockbuster" than the quieter stories I get the feeling you are after (plus there are a lot of guest heroes). Those are both storylines from that era that have been collected in to trade paperback.

You might also try SUPERMAN: FOR ALL SEASONS by Jeph Loeb and Tim Sale, which was a four-issue mini-series from 1998 and has been collected in trade paperback. It is set in the early days of Superman's career.

Greg Rucka's run on ADVENTURES OF SUPERMAN (circa 2004-2006) might be to your liking, as well. I don't personally recommend it as strongly as the other stories I listed, but that is not because of the quality of the writing or art. Neal Bailey of the Superman Homepage has said this is among his favorite Superman runs ever, and board regular rc is quite fond of it, as well. It has all been collected in trades; I can get you issue numbers or trade names, if you need.