First boat that I legitimately owned with my name on title etc; 12' mod-v with a 6hp Johnson. Duck hunting/fishing rig. Second, 12' jon with a 6hp Evinrude, still duck hunting/fishing rig, but customized to suit my needs for fishing quite well. Along the way I have had full access to my dads boat; first a 17' Crestliner Sportfish, full walkthrough windshield. Then once he realized I was all about bass fishing and we got into tournaments, Ranger R81sport. I use this boat now the majority of the time, love it as it does everything I ask of it.
As far as your first boat, if you are not looking to get on big water; dont overlook a simple 12-16' jon boat. Put a casting deck on the front half, throw a bow mount trolling motor on there, and you have a fishing machine that you can afford and pay for in cash.