Read War Zone 1-5. Though it was newer than I thought it was going to be, I enjoyed seeing him ******** with the Avengers. xd
I'm reading a book of his early appearances next.
Essential Punisher Vol. 1's great for his early appearances. There's some fun, if slightly dated, stories in there.
That's the one I'm reading. I'm not a huge fan of Amazing Spiderman and I thought he was underdeveloped in those first few appearances. The Punisher Special Preview is what it's all about. Haven't read the Daredevil one yet either.