I started out in Linux dual booting. (I still dual boot on my laptop for purposes of having Windows for the office.) Over time, I've fallen way from dual boot on my home systems and simply installed Virualbox and then Windows XP in VB.
I now run PCLinuxOS andwhen I need Quickbooks, I boot up VB and then log into Windows. i can then launchQuickbooks. With enough memory and processing power, there's absolutely no change in performance. In fact, Window runs FASTER in VirtualBox because I'm not using it to surf the internet, so no fear of becoming infected. wihoutthe fatru of virus attack, I don't need to install antivirus, etc. Windows XP is safely running inside Linux.
Plus, when I upgraded my system, the folks up here helped me, through instruction, on how to move my Virtualbox file from the old system to the new system. so, there was no need to re-install Windows and all its applications. I just moved one VB file.
So, I would try dual boot first. Once you've got the hang of Linux, then go for a VirtualBox install and run Windows inside Linux. It's faster, safer and simply better.