Good reason to move to DreamHost if your old hosting company email has been down for 26 hours.
If your old hosting company is currently bouncing email then the sending server will keep trying for up to 5 days (depending on sending server configuration).
So if you move to DreamHost, you would change your domain nameservers to those of DreamHosts and after a period of propagation your email will start to arrive at your new host.
There will be a period until DNS caches around the world are updated when you could receive email at both locations.
DreamHost have a wiki that you can look at at http://wiki.dreamhost.com/index.php/Main_Page
You may also find this page of interest.
http://wiki.dreamhost.com/index.php/DNS_-_Viewing_site_before_DNS_change
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Norm
Opinions are my own views, not DreamHosts'.
I am NOT a DreamHost employee OK!! 
You act on my advice at your own risk!