Consider some simple questions:
1. Do you plan to ride in bad weather?
2. Will you have to leave the bike exposed to thieves and the elements?
3. Will you carry loads or keep a stock of clothing at work and travel light?
If the answer is no, no, no, then get the best road racing bike you can afford and have a blast. I do a 50km round-trip commute on a Specialized Festina SL 3 to 4 times a week. This is a no-compromise racing bike since, for me, the commute
is race training.
If you need to carry loads, look at a fast tourer/audax bike. If you plan to ride in really bad weather, think about fender clearance. Better yet, get a good rain suit, forget about fenders and use your current bike as a rain bike. I ride my old Nishiki Professional when it looks like rain. If it's already raining, will just take the train, except in summer when it is hot and the rain is unavoidable.