Sorry, haven't logged in for a few days, belated comments...
I also have domains that just require registrar, no hosting, as hosting is by google apps for mail and elsewhere for websites.
I used to use freeparking. Very very easy to use, but only support is by web. For more techie users, I have found their DNS controls lacking. Plus, I almost had a domain expire once when they accepted payment but forgot to re-register, although it was quickly resolved once I reported it. Would have been nice to be able to phone them, though.
Prior to google apps I used freeparking's mail forwarding which worked OK and was easy to set up, though I sometimes had doubts about the occasional vanishing email.
I've now started switching to Vidahost. Much better DNS controls for techies but perhaps assume users more techie knowledge, compared to freeparking. And of course proper UK phone support when crisis arises. Haven't yet tried any forwarding or hosting.