i and e don't look good in front of just any name. The name must be relatable to internet or electronic. iReptiles.com as someone has mentioned above, is less brandable than other names, because I cannot imagine what could someone brand on "Internet reptiles". But words like iMail.com or eMail.com are 100% brandable and actively searched for, as they stand for internet or electronic mail, a term widely used. eRadio.com would also make a great name, not because search engines would like it(because they would like online-radio.com more), but beacuse the first thing that comes into my mind when I think ofonline radio is exactly this domain name - eradio.com, and it is the first thing that I would type into the navigation bar, before I tried google.
The main point, is that all those "i" and "e" friendly domains are taken, and those remaining available are not very usefull. It would make sense only if you found an end user to sell it to, but dont expect from a reseller to buy it, or to get any type-in traffic.
I have many names like that, and I am only hoping for an end user to contact me, or I will maybe build a brand around them in the future.
Register such a name, only if you think it can be related to "internet" or "electronic", and only if you want to develop it in the future(or if you think that you are good in finding end users).
There is a very nice thread about finding end users in NP, you can read it here I'm sure it will help.
http://www.namepros.com/domain-name-discussion/68798-how-to-find-potential-end-users.html