Just jumping in, I use my impact driver as much as my drill. For driving in screw or bolts, impact drivers are so much faster than drills (and more compact which can really matter). I just built 2 4'x8'x22" planter boxes for my girlfriend using deck screws and then Timberlok screws. No pre-drilling, no issues, just bang, bang, bang and you're done. If you're a serious DIYer, I think you've got to have both.