As a previous thrower, which if played right can be great fun! I used one of the following:
15/21
5PS
5IF
5PT
7Ath
7WM
around 125 in throwing and I chose either 1h or 2h
18/18
5IF
6PT
6PS
6Ath
6WM
around 120 in both throwing and either 1h or 2h
Both of which are nice builds and meant I could use throwing and a melee using 3 stacks of throwing weapons (axes were a personal favourite but jarrids are also a good choice) and a 1h weapon or a 1 slot 2h or if you use axes 4 stacks (since axes are a nice melee weapon too)
However if you aren't interested in a hybrid build and would prefer a pure thrower I would think a build something like this would be nice:
21/21
7PT
7Ath
3WM
and 130 in throwing
this gives you a good punch with your throws and gives you nice agility to run in and shotgun the enemy.
Throwing also sucks with accuracy which is why I think the shotgun approach would work better and after around 120 weapon points throwing only increases the rate of your throws. I must say though I have not tried a pure thrower before so I suggest trying it out with a STF first to see what its like. 7 PT also means you can use any throwing weapon.
As for armour go light, anything bellow a weight of 11. Keeps you light and agile as well as making the most of those weapon points.
I would check out this guide too, it has lots of goodies
http://forum.melee.org/guides/the-art-of-throwing-ii/apart from that I am pleased that you have chose throwing so good luck and most importantly have fun.
