As long as the e-mail addresses are different you won't see a problem. Whereas if they were the same, e-mail would download in different locations at different times and both boxes wouldnt' be synchronized.
Going a little off topic since I believe failurb is talking about two seperate accounts but..
technically, you could use the same email account with both .. set them up as IMAP and/or POP accounts w/mail on the server and the inboxes *should* be the same. The sent items might be different on each client though.. and if you also run the risk of someone setting the POP account to delete mail from the server, etc.. etc..
It's not advisable to use two different clients with the same email account, but it is technically possible.