Mac OS X 10.9 Mavericks
As it's a free upgrade that gives you more apps, improved features across the board, and better performance, there is really no reason not to get Mavericks on your Mac.
Microsoft Windows 8.1 ( Spanish)
If you're a dedicated Windows 8 hater, the update to Windows 8.1 isn't going to change your mind. For everyone else, this collection of tweaks, fixes, and new features is useful, but everything here should have shipped in the original version last year.
Microsoft Windows 8 Pro ( Upgrade)
Microsoft makes an aggressive, forward-thinking, and bold statement for the future of PCs with Windows 8, and vast security and speed improvements more than justify the $40 upgrade price.
Mac OS X 10.5 Leopard
The grace of Leopard's interface enhancements makes productivity more pleasurable with a Mac, as more than 300 functional and fun features top off this update.
Apple Mac OS X 10.4 Tiger ( Family Pack)
Though its new user features have mixed appeal, Tiger's technological changes and speed improvements make this an enticing upgrade, especially for those who passed on Panther.
Windows Vista Home Basic
Windows Vista Home Basic is essentially warmed-over Windows XP, Windows XP SP3. If you're currently happy with Windows XP SP2, we see no compelling reason to upgrade. On the other hand, if you need a new computer right now, Windows Vista is stable enough for everyday use.
Windows Vista Business
Windows Vista Business is essentially warmed-over Windows XP. If you're currently happy with Windows XP SP2, we see no compelling reason to upgrade. On the other hand, if you need a new computer right now, Windows Vista is stable enough for everyday use.
Microsoft Small Business Server 2003
For small businesses that need a business in a box and want to stick with Microsoft technology, SBS 2003 is the only game in town.
Apple Mac OS X 10.3 Panther
Panther adds new and useful features, but at the expense of some old standbys. Current Jaguar users need not apply.
Red Hat Linux 8.0 Professional
Red Hat remains a solid Linux contender, but Windows switchers or dual-booters should stick with SuSE for easier installation.