If this phone performs close to the way others do (all manufacturers produce different firmwares with slightly different hardware settings, so mileage may vary) then you should probably be okay with the 2gb model unless you like to multitask heavily. If you often bounce in and out of apps expecting them to stay open where you were, then you'll run into less issues of apps reloading from scratch using the 3gb model. However, if you primarily use one app at a time, the 2gb model will suffice.
I don't believe there are any other hardware differences with these two models other than the obvious internal storage difference of 16gb and 32gb. Sounds like you don't care about that but if you do, 26gb might be a little light even with the micro SD expandable storage these phones have.