Ever since OS X I've never feared multitasking. While updating, I often leave Mail, iCab and iTunes open. I have 56k, and since Mail and iCab without downloading heavy files, usually take little bandwith and since I have a computer not being the slow-down to the process, I figure it'd be mad to not live every online moment to its fullest...
Updated to 10.1.4 yesterday while posting here...I love OS X