Me1 is definitely worth not skipping. It has the best story of the three and if you haven't been polluted with spoilers it is hands down my favorite. It should not be skipped on a first playthrough of the series. It introduces you to everything that makes Mass Effect, Mass Effect. Yeah after a few series playthroughs it is understandable to skip, it is aging and the combat can be really frustrating, but until then no way skip. Especially with holidays coming up it should be very cheap. No better way to prepare for me4 than a solid first time 1-3 playthrough.
Me2 is very good for companions and personal relationships with an awesome ending. I honestly probably love them all 3 pretty equally after a few playthroughs in each their own ways.