I have no problem with using metro with a cheap sub £10 keyboard and a cyborg rat 5 mouse, aka nothing particularly accustomed to metro. It works perfectly fine, infact I have a windows 8 laptop too with a multitouch trackpad and I find the gestures on that trackpad are no more conductive to using metro than a regular USB mouse and keyboard.
I find the exact opposite actually, I go to move my cursor from left to right across my desktop and find I have just inadvertently triggered the switch metro application gesture, and top to bottom seems to deselect whatever window I have active or I accidently trigger the charms bar, I disabled the gestures. With a keyboard right in front of me I can just alt-tab, or windows+C into the charm bars and for the swipe down I can use this mystical invention called right clicking....
I use both metro and desktop. Primarily desktop I guess but I regularly have the windows 8 messaging or skype apps docked to the left side of my screen (and am quite annoyed that messaging is being removed in 8.1) and I use the mail, calendar and metrotube apps. Sometimes I'll play jetpack joyride too of course :P Most of the software I actually use though is desktop.
When I went to get this laptop, one of the other models I considered was touch enabled but honestly, I havent looked back at getting a non touchscreen model. Metro apps are incredibly functional on just the keyboard alone, no mouse.