I have just started with a new company as their SEO manager they paid for the full Powersuite program but never actually used it.

This is my first time using the Powersuite program so I was quite excited to put it to use.

How important is it to use proxies for either of 4 programs?

I have a budget, I dont want to worry about proxies going down, will it be a good/better idea to get US based private proxies?

If so how many would you suggest, 50 proxies , 100 or 200??

Well, it would definitely be a good idea to use them. Primarily in rank Tracker. You can try getting 20 proxies (max number of simultaneous tasks in Rank Tracker) and see how it goes. Combined with slight human emulation these proxies can be enough for most tasks.

Getting an Anti-CAPTCHA key would make sense, but you need to first determine whether you really need one. If you plan to run a lot of scheduled tasks - it's a good idea to have an Anti-CAPTCHA key for backup.