So I'm going to work under the impression that I've convinced you to go with the taig :D

The things I use the most are a 3" down clamping vice. I actually use a precision grinding vice like this, but there are certainly cheaper options out there. I use a parallel set, edge finder, and an ER16 collet set (either standard or metric on your preferences).

Spend the rest of the money on tooling. For tooling, i'd keep it .25 diameter and under for now. They are cheaper and the mill doesn't have the rigidity to utilize anything larger efficiently. A flycutter is handy as well for facing. Tooling will greatly depend on what types of material you'll be cutting and if you're just doing pockets or 3D contouring. But my suggestion is to buy cheap tools at first...accidents will happen! haha. Once you find you're not breaking tools anymore, spend some money on some decent tooling (i really like lakeshore carbide). You'll be amazed at the cut quality and longevity of quality tools vs cheap stuff.