Windows Live Mail (WLM) is a newer email program, and it basically
has all of WM's features, plus a few extras, like Hotmail access.
I often call it an 'upgrade' to WM, although technically that is not
correct. The reason I often characterize the switch from WM to
WLM that way is because of the seamless way WLM imports all
your WM accounts, settings, rules, emails, folders, etc.
You can configure WLM to look like WM, although it also has
the option (like Outlook) to have three side-by-side panes.
One significant difference is that WLM uses a separate set of folders
(Inbox, Drafts, Sent items, Junk e-mail, Deleted items) for each
account, while WM (like OE) uses a unified set of system folders.
WLM has some improvements over WM, such as the real-time
spell checker (marking typos immediately with a red squiggly underline),
auto-correction of commonly misspelled words, and better auto-
completion when typing in the recipients. Also, when adding a
Contacts group to the address line, WLM (unlike WM) allows the
group to be expanded so you can delete some of those recipients.
If it turns out you don't like WLM, merely uninstall it, and WM is back
just like before.