I personally wouldn't recommend using Netscape any more. They use the same engine system as Mozilla, but are typically slightly behind Firefox and Thunderbird etc.
You have a few options:
Get SeaMonkey, which is an all-in-one thing like you're used to:
http://www.mozilla.org/projects/seamonkey/
Get firefox (a browser alone) and Thunderbird (an email client alone):
http://www.mozilla.com
Both are good, but personally I would suggest going down the Firefox and Thunderbird route since there's much more development focus here.