eurail passes are definitely not a scam, but depending on how much you intend to use them, they might not be cost-effective. if you buy the unlimited ones, then every day you don't use it, you're essentially wasting money. so they're good if you plan on doing a lot of day trips to small towns, and travelling often. also good if you're totally into spontaneous moving about, as in: waking up in paris and deciding you REALLY wanna head to the riviera... NOW.
personally, i'm a huge fan of the discount airlines:
it takes a bit more planning, as the flights get more expensive the closer you are to the departure date. but they can be SO cheap, i've booked flights on a 'just in case' basis, and then just not shown up. or, if you're pretty open-minded as to where you want to go, you can surf the discountair sites and usually find SOMETHING pretty reasonable a day or two before hand.
obviously this limits you to CITIES, and you'd still have to train to smaller towns. so i guess it depends on what kind of traveller you are & what kind of stuff you want to see.
and, more obviously, you have to decide before you go (since eurail passes are not for sale in europe).