I am curious about the most popular ssh client on Windows environment. Talking about me, I use PuTTY most of the time coupled with WinSCP to transfer files. But, I like Tera Term too. It has great drag-drop feature where you can drag a file/folder and drop on the window and it will transfer the file/directory to the host you are connected to. Good one!
What about you people? 
I use putty all the time. The only allowed alternative in my company is tectia client which I find completely annoying
xshell for me..
+ Tab sessions
+ broadcast commands
+ open FTP session
I used to use SSH Secure Shell, Version 3 (the free version - before commercial version). Excellent. I still keep a copy if I need to use SSH in a Windows machine "on the road" although I do not own any Windows machines anymore (replaced by last Windows laptop with a MacBook Air and very happy with that decision!)
You can download SSH Secure Shell, Version 3 here. (Manual attached)
Thank you for the link to download. It looks good to me. I'll use it a little bit more and see. I wish my employers would give me an Apple MacBook instead of Lenovo ThinkPad 
In my company PuTTY and Tera Term are the only options.
@dagio
It looks like you gotta pay to have xshell!! Don't they have an open source version? 
I use putty, and Anita, http://www.april.se because of its extended features. Many terminal emulators fail on function key usage and character translation.
Mine is ZOC, but it is not named here
The poll options are just a few ssh clients I am familiar with (sorry for my ignorance). I use PuTTY primarily as it's approved by my employer and I have been using it for long time. Initially I expected that PuTTY would be the most favorite one. Now I can see that people use variety of other products as well. Thanks for the post!
Putty all the way for me
I use putty for ssh. The more advanced features(single command to multiple servers, etc) I've mostly been able to accomplish in the shell itself.
ZOC Terminal with black background and grey text (Consolas 10.5pt) on a widescreen monitor. Beautiful!
Putty - supports Kerberos/GSSAPI which is required in my workplace, as preferred way of authentication.
And over the years i created a habit using it.
Just tried xshell. It works fine!
I'm happy with PuTTY though (partly because my company does not permit anything else other than PuTTY and Tera Term)
using either KiTTY, cygwin and PuTTY-tray here while in windows