Skunk
For what's it worth I think you should buy a road bike given the miles you do. I reckon your average speed would also increase by 1 or 2 mph but maybe that is not of interest to you.
FYI I bought last year's model of a Lemond Nevada City (made by Trek). It is a standard Reynold's 520 chrome-moly frame (as opposed to a sloping top tube frame), runs with cheap but perfectly acceptable for me Shimano Sora kit, has quick shifters and hidden cables, Mavic XP21 rims, Suntour chainset, looks the biz and weighs 22.5lbs according to our electronic scales, so give or take a pound.
This bike cost me £400 (down from £500). It was that or a bottom of the range Giant OCR, albeit aluminium framed, at around the same price, but I thought the Lemond was more a "proper" bike with the Giant looking like a mass produced for Joe Public version (complete with clear plastic chain deflector on the back hub which I thought looked naff). However I am not one for form before function but, sitting on the Giant and giving it a quick spin just did nothing for me. It is still a nice bike though for a budget buy (i.e. my price range) and I nearly did go for it.
Anyway, I ended up buying the Lemond local since it was on offer at the same price as on the web although generally, where I live, I find I can buy much cheaper on the web than anywhere within 100 miles.
I considered a hybrid but am glad I went for the racer although until I bought eight panel shorts the saddle was excrutiatingly uncomfortable. The fact that I was new to the game might also have lent to my pain!
Funnily enough and talking of hybrids, I cycle most of my time on the top bars except when going downhill when I drop to the lower bars to increase my pedal input and be in easy reach of the brakes (45mph in the Scottish Highlands is easily achievable). I also tend to stay in the saddle, even on hills, but I am finding that I start to come out of the saddle without thinking as my leg muscles get stronger.
However, assuming your hybrid is a road bike with flat bars I have to say I'm not sure I could cycle 40 or 50 miles in an upright position with such wide bars - that's why I would definitely go for a road bike now that I've bedded in a bit. However it's your choice and you should ride at least three road bikes or so to get a feel for it - be warned - they ain't comfortable to start with!
Martin