Dublin, you;ll require a second mortgage!
easyjet fly gatwick to edinburgh and glasgow, , get the party of people sorted well in advance and book as the flights asap, probably £50 each
the flights for summer 2011 went on sale this weekend just gone, so still pretty cheep but will creap up a bit, before settling at a price
Just been looking myself, ibiza and majorca, can be had for about £100
Galway is good for a stag do instead of dublin if your going to come over to ireland.