A few terminal clients I have found useful recently:
PuTTY Connection Manager - A more functional PuTTY. Adds tabs, split windows, and an overall easier to use interface.
SecureCRT - A terminal client known for it's security and loads of features. Many features are included like tabbed connections, easy script generation, terminal emulation, secure file transfer and connections, and a keymap editor. Constantly updated with new features coming all the time.
Poderosa - Simple terminal client that is also multi-tabbed. Doesn't have as many core features but has plugin support. Seems a little dated and lacking in development but has a good simple interface.