I suppose you could, but you'd have to be of course 100% sure that the place you were moving it to was secure, I wouldn't think if you have a lot of Bitcoins on you keeping it all in one place would be a good idea, i know it might seem unlikely, but if someone did ever get wind of where you hid your Bitcoins then if they were all in one location they'd all be gone and then you'd feel like an idiot for not spreading them out into batches. As far as I'm concerned no place can be 100% secure though so that's why I'd keep it on several addresses and on several machines, that way if one goes down then you don't have to deal with a huge loss and have a chance of stopping the person trying to steal from you.
Oh and having more addresses to move Bitcoins from also attracts less attention from the authorities as well as criminals