I flew 48V to KCUT to visit my dad in the hospital this weekend, who is starting to show signs of improvement in his condition. Yeah! But, instead of flying direct to Rapid City and bumming a ride to the hospital, my brother in law asked that I come to Custer so we could drive to Rapid City and discuss a number of family issues that are going to need attention soon along the way. Of course, this started the mental wheels turning and began the distractions. I noticed it was taking me a bit longer than usual to get my act together at home in the morning. Reading thru the weather required a number of passes on the same information to actually "get it". I rented a C-172RG Cutlass that I've been flying for a while, and am comfortable with this plane. Preflight went smoothly... except for "I wonder why the hydraulic reservour is not on this checklist? Did I miss it? Hmmm, nope, it's not on the list. Oh well, check it anyway." "Plenty of fuel to get to Custer with plenty of reserve, but I might as well fill here, since it's cheaper than Custer. Then I can do a round trip without refueling." So, we tow the plane over to the fuel pumps for a fillup, which put me a little behind my desired schedule. However, since my brother in law lives near the airport, he doesn't drive over to pick me up until he hears me go overhead, anyway. So, all fueled up, startup, taxi and runup are all routine and normal. "Beep, Beep, Beep...rats! GPS batteries are low. Oh well, I'll change them once I'm on my way." Everything else looks good, the weather's great and it's a good day to be flying. I announce departure, take position on 33 and give everything a quick check. All looks good, so power up and we're rolling. Cool! It sure feels good to be flying again! Airspeed's alive, everything's normal. there's 55, rotate, and accelerate to 80. "Oh yeah," I remember, "they want us to modify our north departures now for noise abatement for the new housing developments that are surrounding the airport. Ok, glad I remembered that for an early Saturday morning." So, I roll the RPMs back to 2400, turn west between the houses to the road, then north a little, west again and then north to my departure heading. "OK, where was I? Oh yeah, Climb checklist ... there it is, Enroute Climb: normal speed: 86-95, check. Prop: 2500, ok we're clear of houses, back to 2500 RPM. Throttle: 25", yeah right ... 23" is the best we're getting at 7000'. Carb heat: cold, check. Mixture: set for 50° ROP EGT, Cowl flaps: open, check." Something's still not quite right here, but I can't quite put my finger on it. So, climb up to 8500, level off, and we'll see what we get for airspeed today. Quartering tailwind at 20 knots ought to help a bit this morning, but I'm sure I'll pay it back coming home. So, Cruise checklist: Prop: 2100 - 2700 RPM, 2400 feels good so check. Power 15"-25": indicating 22", check. Trims: adjust. Cowl flaps: Closed, check. Ok, so why am I only getting 110 knots here? Ok, flow check... Throttle, check. Mixture, reset to 50° ROP EGT, check. Flaps are up, cowl flaps are closed, gear is down and green. Airspeed still indicating 110 knots. One more time, flow check... until I get to gear - down and green... DUH!!!! Aw crap! Hope nobody saw that on departure! 110 knots - still ok for gear, so "gear up" .... ka-thunk, ok, gear up and indicating... and, to quote Jackie Gleason "away we go!" Ah! 130 knots! That's more like it! I realized that I let the noise abatement distract me from my takeoff and climb checklist and completely missed "gear up". And then the second realization was "If you can miss 'gear up', you had better pull your head out and make a HUGE mental Post-It note to not forget the gear DOWN at Custer!"