As others have said, it depends. As yourself: What is your route like? (smooth tarmac? bumpy tarmac? off-road?) How long? Are you very fit and fast, or fit with stamina, or not all that fit? Do you have much to carry, are you happy with a rucksack, or do you prefer panniers? Do you have moderately secure parking for it at work? (will a flashy looking bike be safe?) Do you cycle apart from commuting?
As you already have a tourer, I wouldn't get another, unless yours is very worn out and needs replacing. If you want to cycle for leisure, why not stick with old faithful for the commute, but go for a bike specific to what you want to do at other times - fast road rides, or off-road?
It's probably fair to say that the one thing you won't need, is a full sus (or even front sus) MTB with knobblies, unless you commute across fields.
Personally, I commute on one of two bikes - my summer hack is a Giant FCR (flat barred road bike) with rack and mudguards added, my winter hack is a no-name MTB frame with chunky wheels and Big Apple tyres, and hub everything - it's probably a sort of hybrid.