I do have enough coins to buy another incubator, but also enough to increase my Pokemon storage. I'm thinking of getting more storage, but what if they gift us (for Christmas) with more space? I'll just have to try get more gyms so I can buy another incubator while keeping coins to upgrade storage.
I am a big believer in finding more Gym's and holding them to claim more.
I believe its worth more to claim every 21 hours for 10 gyms.
do not try and take down enemy gyms, find your team gyms, preferably level 8 or 9 gyms, and train them up and add a pokemon. find a team mate in your area and do a nice long gym run.
and incubators are definately a better purchase then storage.
I have 600 items bag space, 400 pokemon storage and I always have 9 incubators.
incubators give you high IV pokemon, this gives you things to prestiege gyms with, OR those pokemon you do not see often (or junk) as well as more candy, and a lot of stardust.
hatching eggs should be the highest priority.
for me, it takes about 2 to 3 days to hatch a 5K.
claiming 100 gold a day, gives you 300 gold or 2 incubators every 3 days.
use infinate incubators for 2KM eggs.
leave 10km eggs until you have 9 of them. this allows you to save an incubator slot over time.
I currently have 3 10K eggs. only 1 is after the event.
and I have 6 5K and 1 2K egg incubating right now. I want to hatch them all today. (yay straight line walk for lunch!)