Donegal county coastline is absolutely stunning: waves crashing into the shore, seacliffs like Sliabh Liag (Europe's highest), small bays like one in Glencolmcille Gaeltacht village. Roads are very good (brand new or well kept old ones), access to every landmark is very well maintained. But the main treasure of this place is people: very friendly and ready to help with smile. As there is no bus from Carrick to Slieve League cliffs we decided to hitch-hike and met an amazing couple from Glasgow (though with some Irish roots). They not just gave us a lift there but actually drove us from place to place till sunset! And then as it was just around the corner offered to drop us at Killybeg - 27 km off the course! Such kindness is a real gift!
Killybeg is Ireland's busiest fishing port and home to Donegal carpets (1878) which grace the White House and Buckingham Palace.
In Donegal town the Castle is worth a visit - the 15th century Seat of Power of the O'Donnell clan (4 euro ticket, open on Sundays). Donegal Craft village (just outside of town) was established in 1985 and has become a showcase for contemporary arts and crafts in Donegal. It offers the ideal opportunity to see the experts at work! The ruins of a Franciscan friary (Donegal Abbey) founded in 1474 could be seen even today (beside Tourist Information Center).
Bundoran lies just a short drive from Donegal town and is very well known surf destination in Ireland (it will host the Eurosurf 2011 surf championships). There is a lovely promenade in the town (you will for about an hour and wind-proof clothes). Be careful while filming or taking photos - wind is extremely strong and blowing in sand and salt! But it's beautiful and definitely rewarding.

Donegal mussels, chowder and even traditional fish&chips are a must (I have never tasted such a tender fish like here in Donegal)

So if you want to experience real Irish warmth and have some craic go to Donegal county!
In Bundoran
At Franciscan Friary (1474)
In Teelin
At Slieve League sea cliffs
In Bundoran
15th century Donegal Castle
Sliabh Liag - Europe's highest (601 m) sea cliffs
The rain lake at Slieve League
Mount Errigal