I have been running Ubuntu 14.04 LTS on this laptop, an HP ProBook 4540s for nearly 3 years with great results. It has an Intel i5 processor with 8 Gb of memory and an 750 Gb hard drive.
I went to the local computer store and bought the machine with Windoze 7 already installed, I blew it away, reinstalled the Win 7 system with a GPT partition table instead of the usual MBR disklabel and left plenty of room for Linux. That allows me up to 128 partitions instead of the usual 4.
I have the windoze 7, Ubuntu 14.04LTS, CentOS 6, and room for more. I am going to upgrade the CentOS 6 to CentOS 7 soon and add OpenSuse.
Of course, you don’t have to do like I did to get a good Linux machine. You can look at emperorlinux.com, thelinuxlaptop.com, zareason.com, or system76.com, all of whom sell Linux laptops and desktop machines.
I can tell you the Windows 7 rarely gets booted as I use the Ubuntu system most of the time.