Well personally I use Strava on my phone as a bike computer. Some people don't like using their phone as a bike computer because it can eat up your battery, but I just keep one of these in my bike bag.

As far as locks are concerned, the most important thing to remember is that even the best, most expensive lock is just a deterrent. What type of deterrent you need depends on where you live and where you plan on leaving the bike. Are you going to leave it in the same spot every day for work, are you going to leave it outside your home or apartment, etc.