I'm so fed up of solid colour (black, grey, white) hoodies with the only design being some branding or some pointless slogan. There is a niche for high quality, well thought out serious cut & sew clothing design.
A company who i feel that have really though about what a riding hoodie needs is AMC Development
have a look at the features on their zip ups for this year http://www.amc-development.co.uk/zipups-21-c.asp
the rest of the site is a bit of a mess atm.
Personally I'm a massive fan of geometric shapes and straight cuts (i.e. 1 or 2 cuts of different colours, like a sleeve of different colour and a angled cut from ribs->waist, across the hoodie, etc) but not patches and pockets of different colours it looks trashy.
sparknotes: thought out design & features in colours other than solid black, grey and white.