I can tell you that Shure is the best option when it comes to isolating ear buds. They have incredible sound! And later, when you've got some extra cash, you can have custom ear bud sleeves added to them to make them fit your ear perfectly snug. These are just under $80, but well worth the investment. http://www.amazon.com/Shure-SE110-Isolating-Earphone-Balanced/dp/B000VHRDUW/ref=dp_ob_title_ce
I'm currently living off a $10 pair of Philips headphones which, despite being cheap, have actually performed way better than the stock Apple 'phones that came with my 4G Nano. Problem is, they fall out of my ears a lot when I'm walking to my bus and am looking at some in ear head phones to help remeby that. I'm also in need at some noise cancelling headphones for long journeys (for full size models, pretty much my only options are the Sony MDR-NC7s cause of price). Would it be better to just get one pair of Sound isolating In ear 'buds (the V-Moda Vibes come to mind), or get the Sony's and another $20-$30 in ear pair. Keep in mind im on a $70-$80 budget.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic