So I've got $600 to spend on gear, what should I get? My company's insurance gives me $100 a month to spend on "health and wellness" stuff, and I'll have 6 months saved up when I'm quitting, so what should I get?

I currently have: 

A 3 man, MSR Mutha Hubba (thinking about getting a hammock for a lighter option)

Heavy backpacking boots (maybe some trail shoes?)

A Trangia stove kit (maybe a multifuel stove?)

I'm happy with my MEC sleeping bag

I have a bulky but solid ThermaRest inflatable, I've been debating upgrading to a Prolite or something similar but haven't made the move yet. 

I'm doing a couple week long biking trip this summer and besides that do 2 or 3 day hikes when I can. I haven't gone on any extended trips but wouldn't mind being ready gear wise should I ever do one. So, what should I buy?
