Your Sent Mail box

This depends a lot on whether you will be mostly working online (IMAP) or offline. If you are working offline (downloading via POP3 or equivalent), the following is good enough:

set copy=yes	#keep copies of outgoing mail.
set record="/home/randymon/Mail/sent-mail " 
#This is for locally stored mail

If you're using IMAP, then you should store your sent messages on the server, as follows:

set record="=Sent Items" 
#This is for the `Sent Items' folder on an IMAP account. 
# Note the equals sign, which makes it clear 
# this a subdirectory of the inbox.

And if you're using offlineimap, you can store your sent messages in the local Sent Mail repository, and will sync up to the IMAP server when offlineimap runs. Use

set copy=yes	#keep copies of outgoing mail.
set record="/home/randymon/.mailcache/INBOX/Sent"

Lastly, an advanced trick: you can specify which folder to use on a per-message basis using send-hooks (see section 4.10).