I have already competed in a few sprints and am ready to commit to a bike, but not necessarily a tri bike. I did the past sprints on a mtb (and it nearly killed me...)

I am thinking of upgrading to either a road bike (Fuji Newest 4.0 or Jamis Ventura Sport) or a cyclocross bike (Surly Cross Check or Bianchi Axis 2006 or Bianchi Volpe). These choises are based on what they had at my LBS, but I am open to other suggestions in my price range (<$1000).

My big question is whether to go cyclocross or road bike - I need something versatile that I could use for bumming around Philadelphia and for sprint/olympic tris including one off-road tri. Do most people ride cyclocross or MTB in off road tris?

I suppose I could also use my MTB for bumming around Philly, but there is some appeal to the cyclocross bike.

Is there a big performance difference on short tris between cyclocross and road bikes?
Any thoughts would be much appreciated.

thanks,
Jon

If you put thin (25mm width or less) and slick tires on the cross bike, it will be basically as fast as a road bike in a short tri. Consider buying some clip-on aerobars to throw on the bike for triathlons, as well.

If you put thin (25mm width or less) and slick tires on the cross bike, it will be basically as fast as a road bike in a short tri. Consider buying some clip-on aerobars to throw on the bike for triathlons, as well.

+1

My cyclocross bike (which i use for commuting) is extremely similar to my road bike when i have skinny 700x23 tires on it. :)

Thanks guys. Any thought as to the particular cyclocross bike to go with - Surly Cross Check (steel) or Bianchi Axis (Easton Ultralight tubing). The specs for each are here:
Surly: http://www.surlybikes.com/crosscheck_comp.html
Bianchi: http://www.bianchiusa.com/06_axis.html

Going by the way it looks I am leaning towards the Bianchi but that may change once I test ride. Also, any thoughts on steel vs. aluminum? Are there other bikes (jack of all trades) that I am missing out on in that price range?

thanks for all the valuable input so far.