Hard to suggest anything without knowing your particulars like budget, look, environment, but if your going with only one vest you should buy OD or Coyote. Dont buy a vest that is camo, you change uniforme you will have to buy another vest. If you buy only one vest, go with Coyote because your vest will go with any camo uniforme. Coyote (the brown-green one, not the tannish one) blends with a lot of environments. When you buy pouchs, you only buy Coyote, you dont end up with a ton of pouchs that only match some uniforms. Buy a MOLLE vest, the kind that comes without any pouchs. Try a lot of vests, dont buy without trying it on, what is slightly annoying for a few minutes becomes hell after a few hours. What is hot in the store becomes a furnace in the july sun. Now buy a few mag pouchs and add as you need.
Dont buy black, tan, ACU vests unless your going for a particular look, they are specialised for particular environments and you will stand out in every other environment. If you really dont like Coyote then go for OD. Finally, buy a good brand, Condor is not to expensive if your on a budget. Dont buy cheaper, you wont save any money and will endup spending twice.
If you want to save money, buy a used vest with all the pouchs included, try it in a store before buying on the Internet.
Hope this helps
Take care.