One of the minor annoyances in Skype 4.0 (which will soon be the default release) is that its determination to promote new features like video calls means that it makes some everyday tasks harder. For instance, where double-clicking on a contact name used to automatically start a voice call, now it brings up the contact card and you have to separately click on "Call phone" to make a call. Frankly, it's an idiotic design, because single-clicking also brings up the contact card. Fortunately, there is a setting to make Skype behave more sensibly. Choose Tools, Options and then select "When I double-click on a contact start a call".
While it would make far more sense to make this as the default behaviour, at least there's still a choice.