"Will I get SQ on par with the HD555?"
Probably not, at the price of the E2s and below. The general rule of thumb is that you'd have to spend twice as much for an in-ear (canal phone type or IEMs) as you would for headphones, to get comparable sound. That may be changing, so consider it just a general rule of thumb.
What you do get with canal phones and IEMs is exteme portability (and stealth, if you need it). In noisy environments, you won't have to play your music as loud, especially if you get IEMs -- you'll have the best hearing in the retirement home. And, compared to mere earbuds, canal phones and IEMs tend to stay in the ear, which reduces the aggravating fit/stability problems that can come with bundled earbuds.
The Creative EP 630s do have some cord microphonics, but I really like them for $30 or even less. They're similar in form to, and less expensive than, the Sennheiser branded canal phones, which also get good reviews. Note that the Sennheiser canal phones have the non-symmetrical cords, with the right earpiece's cord meant to drape around the back of the neck ... some people don't like that, and some people do.
If you really need isolation, I can recommend the Etymotics ER6i's (a pleasure to use on loud forms of transportation), but I wouldn't count on them reminding you of your HD555's. On the other hand, they will be very clear (unveiled) and detailed for the price, and with correct fit you will get bass ... but you will hear it rather than feel it. The Creative or Sennheiser canal phones will be "fuller" sounding, if that's what you're looking for.
If you stretch your budget a bit, there's the very fun (but not really isolating) V-Moda Vibes, and the isolating Westone UM1 IEMs.