Flat steel mainspring housing (strongly prefer checkered at 20 or 25 lpi).
Standard GI pattern grips, full checkered or half checkered (Ahrends' "Tactical Pattern")--never found the double diamond pattern terribly appealing. Thin grips make the gun more comforatble for carry but I don't like them for shooting.
Long trigger (prefer solid aluminum or CMC or STI over three hole types for asthetic reasons).
1911 means single stack. I only have a Government Model right now, but I wouldn't mind trying a Commander. Don't think I'll ever get one smaller than that.
I prefer a high ride beavertail grip safety with a pad. My favorite is the Caspian; second favorite is the Wilson #298.
Extended single side thumb safety is close to a must have. I prefer the CMC. Second choice would be the Ed Brown Tactical.
I like a checkered front strap at 25 or 30 lpi, but I can do without it.
For a defensive weapon, I have come to believe that the XS Big Dot express sight system is a distinct advantage.