Still secure? Skype hasn't been secure for a long time. Sadly, people keep on using it... There's tox.im, but I heard the coders write like 1-line of code every other week, so it's gonna take like 3 years for it to be done... Hopefully we'll get a real skype alternative before then..
Basically stick with anything that uses standards. OTR (Off-the-record) is the standard for text based IM. ZRTP/SRTP is the standard for VOIP Audio/Video encryption. Also if you are using ZRTP/SRTP ensure the software either uses CBR (Constant Bit Rate) or at least has the option to disable VBR (Variable Bit Rate). As there are some attacks against ZRTP/SRTP if you are using Variable Bit Rate. More information over here. Of course try sticking to opensource and reviewed code when possible