Considering the mantra at Strobist and amongst most photograhers is "Get the **** flash off the camera", and with good reason, um...not so much. Getting the flash even a little off camera is very important and opens a myriad of options to you. I suggest you understand thoroughly why they highly encourage you to get the **** thing off camera before you consider using it on camera for any length of time. You can use flash on the shoe effectively, to be sure, but it takes the knowledge of knowing its limitations and not trying to go against them.
Having the flash on the camera limits you. Always.
If you need to use flash indoors in tight spaces and you're shooting fast (running and gunning, so to speak), I highly suggest getting the Presslite Vertex. It works wonders indoors. Not very helpful at all outside, but it gives an immense amount of control inside with ETTL/iTTL.