okay i got it.
this is an insane itinerary for too short a time. by the time you get to amsterdam, the only thing you would want to do is to sleep. and it will either be very expensive or you will be spending disproportionately long periods of time on transportation. my suggestion would be to not go to italy, spain, and portugal and spend more time in the UK (esp. london), switzerland (esp. luzern/interlaken - mt. jungfrau) and france.
fly into london, take easyjet from London Luton Airport to Zurich, travel by train throughout switzerland, france and holland, end in either paris or brussels (belgium), get back to london by EuroStar, and then fly back to hk from london. a lot cheaper that way too.
but to answer your questions:
if you HAVE to stick to your itinerary, the eurail global pass (15 days) is your best bet. it is the easiest to use - it is valid for 15 consecutive days after you get it validated at a train station where you start. but be aware that the pass does not work in the UK. if you can trim your itinerary to france, holland and switzerland only, you can use the eurail select pass (3 countries) - and depending on how many days you plan to be on trains, get the one with the right length of time.
http://www.eurail.com/eurail_select_pass_3_countries?currency=eur
i do not recommend driving in europe at all, because it is expensive - both rental and petrol. unless you have to get to places that are otherwise unreachable, or money is not an issue. big cities in europe have very good public transport networks, and the cities are generally pretty tourist friendly with clear signs to most tourist attractions.
as a general rule, i recommend staying in all big cities for at least 3 days, and head to the countryside if you can (you aren't even planning to stay for a while to appreciate the alps when you are in switzerland!). if not it is seriously pointless going there.
2008-12-29 12:52:41 補充:
and within the UK, you can use the National Express:
www.nationalexpress.com
to travel between cities. unless you know the trick to getting cheap train tickets, it is very expensive to travel by train in the UK.
2008-12-29 12:55:14 補充:
or you can fly back to london from amsterdam by ryanair or easyjet (both or either one should have service). that can even be cheaper than eurostar but a lot less convenient.