Assuming you want something in a polymer frame that you can buy new off-the shelf, I'd say:

Walther PPS is you want a small 9mm. Great gun (also available in .40 S&W)

Walther PK380 for a .380

For more money, and a metal frame:

SIG P239 in 9mm
SIG P238 in .380
Walther PPK in .380