I always pan bass a few clicks off-center...usually to the right, at about 12:30.
Besides bass, I also split/pan my kick and snare...about 11:00 (kick) and 1:00 snare, and I rarely have two elements occupying the same position...more like never.
I like to leave that small space in the center open for my lead elements...vocals, guitar, etc.
Panning bass a littler off-center will not be really noticeable as "panned", because low-end frequencies tend to sound mono anyway (2.1 or 5.1 setups use one sub, usually placed off to one side)...and since I pan bass to the right, it only makes sense to put the kick a little to the left to balance things out. Also, with the Snare a little off-center, when you have big hits and lead vocal/guitar notes all on the same beat, you don't get as much peak energy build-up in one spot.
Plus...I don't like when I hear a mix with bass, kick, snare, vocal, lead, all in the center...and then just two rhythm guitars or keys panned off to the sides. It sounds strange to me, and at that point you might as well just mix in mono.
I prefer to fan out all the elements, since there is 180° of L/R image that can be used, so why jam it all up the middle?