What is the best remote desktop tool to connect to Windows from Ubuntu? [closed]

You can try remmina. While it uses the same backend as tsclient and friends (the backend being rdesktop). It has a more pleasing UI when compared to tsclient.

Ubuntu ships by default with tsclient. It works pretty well for me.

Try rdesktop

rdesktop 192.168.1.23 -k de -g 1500x1150  -r disk:mydisk=/home/soma

Parameters:

-k de............................ set keyboard layout
-g 1500x1........................ set resolution of the rdesktop window
-r disk:mydisk=/home/soma.........share your home directory with the remote machine

KRDC, which comes as part of Kubuntu, allows better control of the appearance of the remote window than just using rdesktop or tsclient. In particular, it allows a full screen view that you can minimise, unlike the other two, which (as far as I can tell) require you to log out to return to your Ubuntu session if you are using full screen.