Of course, the recently released Firefox 4 has a sleek and enhanced look, but if you prefer the minimalistic design of Google Chrome over your Firefox design, you can enable this very easily with a simple add-on FXChrome.
It’s quite simple to add to your Firefox browser. Just enter the FXChrome add-on page and install it. After finishing the installation, restart Firefox. Now Firefox should look exactly like Google Chrome.
Note: One problem I noticed with this add-on is that, it misses close button on opened tabs. To close a tab, you need to right click and choose close option.