I am using a Byonics MicroTrak RTG. It's a great APRS setup to get started with, as it comes from the manufacturer pre-programmed and is a "plug & play" option. I replaced the included magmount antenna with an inexpensive steel whip from Amazon. I already had coax run to the antenna mount from a previous CB installation, and used this NMO to PL259 adapter.
My base station IGate runs DireWolf. I used an old Baofeng BF-F8HP with a battery eliminator, an audio interface cable, and a USB soundcard to connect it to a PC running Linux. I built a simple 1/4 wave groundplane antenna to get everything up and running and it has worked well so far.