Ditto on the Etymotics. I've used the ER-6i for about 4 years now. Still outstanding noise isolation, superb sound quality. A check of their website shows Etymotic now sells this for $99, and they have a less expensive alternative, the mc5 ($79) with equal or better specifications in all areas.
I've seen the ER-6i appear on sale on several websites for in the low $80's over the last two years, though I find none right at the moment from any online vendor I've done business with. I noted, however, that Best Buy is listed as an authorized dealer, but no ER-6i or mc5 models show up on their website. Local stores may have some in stock.
They really are quite good.