With the introduction of the new fluid thumbnails, many users started complaining that they want a fixed grid view. I personally love the fluid one, but it is extremely easy to fix this for those who want a grid, using local CSS formatting.
All you have to do, is install the browser addon Stylish, and install a User Style.
(If you use Internet Explorer, please switch to one of the three browsers above. They are much better anyway. My personal suggestion is Firefox.)
P.s.: Only install or have activated ONE of the two at a time, or they will conflict!