I ... would like to know if it would give me greater peace of mind to upgrade to (any) paid versions.
How can anybody else know what would give you greater peace of mind? Depending on who you ask, paying for antivirus software is either a good investment or a total ripoff. In reality, neither viewpoint is accurate. You can find plenty of good reasons to choose a paid antivirus product, and plenty of good reasons to go with a freebie. Four basic levels of antivirus products exist: free, paid antivirus, suites, and "premium" suites. As you move up the ladder from free antivirus to premium suites, you typically get more features, such as identity theft protection, firewalls, parental controls, and system performance tools. Free antivirus software usually provides a bare minimum level of protection. It will scan for malware, and often can perform automatic scans, too. Paid antivirus straddles a middle ground between the basic freebies and the feature-packed security suites: They typically offer more comprehensive security tools (such as parental controls and identity theft protection) and more flexibility than a free antivirus package, but they have fewer additional features than suites, which are intended to be one-stop security shops.
One thing that the "you get what you pay for" people may sometimes overlook is that many free antivirus products are good products which are "paid for" by advertisers and pushers of adware/foistware/toolbars that you have to be alert to opt out of at install time, and many paid for (by you) suites have lots of bloat and stuff that not everybody wants or needs. Every supplier of antivirus products that come in free and paid for versions says they treat both types of customer the same when it comes to virus definition updates.
