I got one last year on the bike to work scheme and got a cyclocross bike - it's light, not quite as light as a road bike, but light enough I can easily throw it over my shoulder to carry - I'm a small female and certainly would not have been carrying around my old bike. It feels to me far more sturdy than a road bike, I've a lot of bumps on my commute and I feel it's more than able to handle it. It's designed to be used off road, but without the weight of a mountain bike/no suspension. It doesn't have as many gears as road bikes, I guess about 12 - but the range is more than sufficient for me to head up the hills in Dublin/Wicklow.
It will be the upper end of the price range in terms of the cycle to work scheme - 1000 euro plus without accessories for a basic cyclocross bike. But I really love mine - it's what I'd always wanted without being able to articulate it. It took going in to quite a few shops to get one that would sell one in my price bracket and quite a few tried to convince me to get a road bike with thicker wheels or a hybrid. This was, by a long shot, my favourite bike. I use it for commuting, the odd spin out the country (40-60km) and I know it can handle something off road like the conemara challenge for when I get my butt in gear and get out there. I would absolutly consider using it as a starting bike for triathalons - mind you while I've done the training for one, I haven't actually completed one. When I get there, I may be looking for a road bike then! But given my mixed requirements - lot of commuting/some road biking/maybe some off road work, I consider it the perfect fit for me.
It's a pleasure getting on this bike versus my last hybrid (which I had modified for the way I like with drop handle bars, etc..) but was just so heavy. Have a look at some and take them out for a ride - I've a Giant TCX.