Monero Clinet.Net has been recently renamed to MoneroX (you may check the interview with the developer here) and appears to be a decently workable GUI. Now it runs natively not only on Windows, but also on GNU/Linux and MacOS. You can easily download MoneroX from Github. If you need “how-tos” to run Monero on Linux, watch instructions here.
You may also learn and try other Monero clients right here.