Now, if the OP had asked which are the top three paid and free email services which don't get talked about a lot, that you personally use.
Paid:
1. Fastmail - this is the only paid email service that I currently use. I have domains which require an annual payment and they are hosted with GoogleApps.
2. Polarismail: I was given a free account over at EMD but I believe those are gone and it's a paid service. Actually quite reasonable costs.
3. Eumx.net: Same exact deal as Polarismail and I think they're even cheaper.
Free:
1. Again, Zoho
2. Yandex
3. Lavabit
I mostly use my Google Apps accounts but I will on occasion use all of the ones I just mentioned.
I'm really considering hosting a domain with Polarismail as this service looks quite promising and support is excellent for the costs involved.
Fastmail, I will probably drop at sometime in the future as I really don't like where they're going. Latest changes to the web interface were not to my liking.
Eumx.net is another excellent service. The few times I needed support it was quite fast and resolved the issue. Their website leaves a lot to be desired, but they offer four different interfaces. OWM, Horde, Squirrelmail and Roundcube. I don't know of any other service that does that.
They're a contender along with Polarismail as far as domain hosting goes.
I'll leave you up for air now.....