Having a good array of fonts to choose from is important. These 3 fonts have met my needs in many situations, and I'm sure they'll help you too! The best part about them is that they're free.
Aller
If you've been paying attention, you might have noticed that this is the font I use on the home page of my site. It has a few flavors, including a more blocky display version (also featured on my site).
Qlassik
I first found classic for a project that ended up being scrapped, but I am glad it happened because otherwise this gem may have gone unnoticed. Qlassik is a great font to add a little flair to a simple look. It's clean, and looks great.
Fontin
I actually found this one when I was designing birthday party invitations. This is definitely the one I have ended up using the most, as it is very versatile and can fit different designs and looks.