Look for 1.7 - 1.8 ohm atties. If your eGo battery is a Smoktech and not a genuine Joye battery, I think it's unregulated. Have you noticed that your throat hit and temperature are stronger on a full charge? If so, it should do around 4 volts under load with a full charge. 1.8 ohm atties do well at that voltage. You might even try a 1.5 ohm atty or two if you vape 12mg or lower nic juice, or if you just want to try a stronger throat hit.
I'm very fond of these 510's and these io6's. I've dripped on Joye, SLB and some unbranded Chinese knockoff 306, 510 and 901 attys; and I think the IKV atties offer the best performance and longevity. And IKV atties don't ship soaked in primer, so they're ready to vape as soon as you unwrap them. Some people swear by the HH.357, but I can't really see myself spending $20+ on an atomizer when (according to Grimm Green) they don't perform any more impressively than similar 510's.
Consider switching to a boosted variable voltage device, such as a LavaTube or ProVari (as opposed to those vv eGo batteries, which should more accurately be called tiered voltage limited). Since I got my ProVari, I've discovered that I seriously enjoy dialing the voltage in differently for different juices. Flavors seem to blend together differently at different levels of power. Additionally, you can get a stronger throat hit using a lower nicotine concentration if you turn the voltage up.
510, 306, io6 and HH.357 all fit on a 510 battery connection.