I've got a spike fin goby and it isn't something I would recommend without a very very specific habitat.
If your tank has no caves or tunnels in the rockwork and all or nearly all of the hiding places available will leave the fish visible then the little fish would make a great addition(but may potentially be extremely stressed from lack of hiding spaces). If you've got normal rock it will have enough hiding places that you'll almost never see the fish.
I've seen mine maybe a half dozen times in the last month and even then it was usually only a glimpse, before the fish went back into hiding. My girlfriend or any visitor has yet to actually see the fish. They are an extremely beautiful(even cooler than the pictures), but extremely secretive fish. Mine seems healthy and happy in my 12 gallon, so it has been a good fit for my tank. Sadly, I can't say it adds anything to the tank as I pretty much never see it.
As far as gobies go I'd look into some of the smaller shrimp gobies. The Yashia is beautiful, the tangora, or the barbershop are also quite nice looking and from what I've read tend to be a little more visible. If I could keep my tank under 75* all the time I'd get a catalina goby. Their colors are absolutely stunning, but they tend to die quickly in tropical temperatures.