I really like Google+ Hangouts as a replacement for phone calls. There are a lot of drawbacks but overall they are much better than any alternative.
Better than Skype:
You can easily set up a video conference call. Skype makes this hard because they want to charge you, and the payment process is too slow to be worth it.
No client install needed. There’s a rumor that Skype is going to WebRTC to get a browser implementation, and that’s very nice from a web standards perspective, but Hangouts work great right now.
Not very broken. There are lots of malfeatures but no more than Skype.
Better than plain old telephone:
More reliable than over a cell phone. Voice calls over cells have a lot of problems.
Video+voice is higher bandwidth than voice alone. Video calls are richer and more effective communication.
Integrated IM is necessary for pasting in links, Wikipedia references, images, videos – things that expand the potential range of communication.
Integrated screen sharing enables showing slides/ doing presentations, which is often incredibly useful.