Dublin, London, Stuttgart region, Italy - first trip to Europe, 3 weeks

I think it makes much more sense to fly into Dublin and out of wherever in Italy you plan to end up. Multi-city flights (open-jawed) are usually pretty comparable in price to round trip flights but even if they are a couple hundred $$ more it's worth it when compared to the cost and time of returning to Dublin. If you do end up with a round-trip to Dublin, the most reasonable way to get from Italy back to Dublin would probably be a flight on a discount airline, otherwise you're spending a whole day getting back there (possibly more).

As noted above, before you book long train rides, check the web for the discount European airlines... skyscanner is the site I use, but I'm sure there are lots of others. They are often far cheaper than train travel. Do check the map for location of the airport being used and plan for that... they often use airports far outside of the city. And be very careful to comply with ALL of their rules/fine print, or the price can go up quickly and dramatically. Finally, the earlier you buy, the cheaper the ticket, although you won't have much flexibility re changing flights.

When searching for airfares, use www.kayak.com. Don't book two one-ways (very expensive); book a multi city (open jaw) ticket, with the first leg being ORD to DUB and the second leg being FCO to ORD (assuming you're finishing in Rome). As said above, even if this is more expensive than round trip ORD to DUB, you'll save time and money backtracking. Yes, unless you have a lot of time, from Dublin to London and from London to Stuttgart, look for a flight on www.skyscanner.com. Just be aware that London has six airports, and it costs a lot of time and/or money to get to some of them.

Keep in mind that Ireland is not part of the UK, so you have four countries on your list. That's a lot for a three week trip- I suggest writing out a list or spreadsheet in which you plug in the number of days you could spend with your friends- then see how much time you have left over for Italy. London and Stuttgart are well connected by air. Germanwings, a popular budget airline, flies out of both Heathrow and Stansted airports in London. As noted previously, check out skyscanner.com for all your options. I agree that you should fly "open jaw" and return to the States from Italy. Rome and Venice, for instance, have major airports with many flights to the US. Whether you have time to visit more than one location in Italy, again, depends on how you budget your previous days. Feel free to come back to the forum with a day-by-day itinerary for additional suggestions. Good luck!

Thank you all for your replies. They are very helpful! I'll post more as I get itineraries in order. The "open jaw" approach sounds very good.