Yet Another Serial Port reader. This has a couple of nice features that I always wanted, and didn't see in other readers.
YASerial has the ability to scan the available ports and will place them in the Ports dropdown menu. This saves you the trouble of heading over to /dev/ (on linux) or the control panel (in Windows) to try to figure out the name of your serial device.
Additionally YASerial will stream incomming data directly to a file if you so desire. This I find is great for troubleshooting in addition to simply saving the data for plotting/analysis later.