I have both the EP 630's and the ER6i's, and I would suggest you go ahead and start out now with an "initial" upgrade now to the EP630's, Marshmallows, or (if you get a good price and don't mind the non-symmetrical "J" configuration cords, where the right cord is longer than the left) CX300's. As a prior poster said, they will later be a good "knock-around" pair if and as you buy more expensive or more specialized earphones.
I mention "specialized" because as much as I like my ER6i's, I use them primarily on airplanes. Their excellent isolation would work well for you on planes, busses, trains, etc. -- noisy environments like that. However, even with the comfortable, good-sounding and easy to insert/take out short Comply foam eartips, the Ety IEMs can take some getting used to and aren't as easy to use in a day-to-day sense as simpler canal phones such as the three mentioned above ... and the really bright, clear sound signature might not be as pleasing to you, especially at first, as that of various canal phones (they cut through plane noise well, though).
I use EP630's in an office environment where I can't have the degree of isolation that the Ety's provide and where I might need to take them out and put them back in repeatedly. Canal phones will fit securely, unlike earbuds, and almost certainly will sound better than what you have been listening to, if only because the sound will be "directed" into your ears. I've read more positives about the Marshmallows' sound than I have about their fit -- some people don't like their stock tips, but the price is certainly attractive. I can say that the Creatives have the soft, flexible silicone ear tips, which are easy to adjust to after bundled earbuds. Sound is good for the money with with Creatives.
Just about any canal phone, would be a (first) step up for you. Brace your wallet, though!
