A couple years ago I used to use Hotmail to do what you want. Hotmail would let me connect to up to 4 mail accounts (3 POP accounts plus Hotmail).
It was great getting all my mail in my Hotmail inbox.
Unfortunately Microsoft dumped that feature.
The closest thing I can see now is you could upgrade your Hotmail to MSN Premium ($9.95/month) and use Outlook Connector to view Hotmail and your external POP mail accounts.
I don't think any there are other mail clients that can access Hotmail so I don't see any other choices as long as you want to keep that email account.
If it's just the Hotmail domain name that you don't like then you could upgrade to MSN Premium. I think that changes your email to email@example.com instead of firstname.lastname@example.org.
Premium would also give you up to 11 email accounts but I don't think you can access them with one logon. There's still Outlook Connector (but I hate Outlook)
<b>56K, slow and steady does not win the race on internet!</b>