You've seen how many bikes I have (albeit with very clear categories- XC race, burly HT, 6" bouncer) and I've never felt like I've taken the wrong bike.
I take them all to Kemback and ride the same stuff, just in a different way. Obviously I'll do bigger stuff on the DH bike and the Evil, but I'm happy doing the first 2 doubles on the racer.
You'll get it clear in your head after a while where you prefer riding them and always choose the right ones. Say, for me, the alps, big mountains and DH= bounce, trail centres/peaks/long days out = HT, short, fast, local blasts and blue routes = racer.
Personally I thought your HiFi was brilliant, and getting something like my Norco would be a great compliment to it.