Well the M3 has been awful for the last 2 mornings at Blanchardstown tailing back to Mulhudard. I dont get why the M3 is meant to be a saviour for the long suffering Meath commuter when the bottleneck of Blanch/M50 is still there. Anyway, the train station at Dunboyne will be ready in 2 years and there is supposed to be a large park and ride conecting with the station near Fairyhouse on the new M3, so transport links may improve from Trim above the current bus service. I am pessimistic about the train line to Navan by 2015, but that's just me. Dont know why they can n't put a lightrail line along the road as they are building it, just like the set up from the new Athens airport.
For 4 years I commuted form Drogheda which required a 30-40min drive from Nobber - yes, I could have gone from Dundalk but there are more trains from Drogheda. The car parking is a nightmare and getting on the train at Pearce and engaging in the mad dash to your car was just plane stupid. I gave up and resort to private bus after a car accident one icy morning a few years ago, but I really miss the train.
I think I'd go for Slane - nice village (fabulous patisserie that attracs people for miles), good connections and the N2 seems like a much better road these days now the by-pass around Ashbourne. The N1 is also handy alternative...the N3 is just a nightmare, but one some of us have to live each day unfortunately.