You can google up a swag of other options, among them is Livegraph, which works fine but I just preferred PLX. If you have an Android device, you might consider Bluetooth Graphics Terminal, which does what it says - via bluetooth - and is ideal for casual use. It can also record data in the usual manner, but does not do local timestamping.
RealTerm is not the same as the serial monitor. It can do local timestamping off the PC clock and record the data for subsequent use. By subsequent use, I mean making a graph in any graph programme or spreadsheet programme, which I assume would include Open Office. The serial monitor is useless by comparison, hence my previous comment.