I am the happy owner of a '03 naked Suzuki SV1000 and an '03 Kawasaki Z1000. I've never owned or ridden a Ducati S2R or the Triumph Speed Triple. But I have ridden a Harley V-Rod and beat one in a drag race on my SV1000 (LOL). I can say though that if you like the sound and power delivery of the V-Rod, you will love the SV1000 for these characteristics. Before I bought the SV1000, I did a lot of research and for me, it boiled down to two main things:
1. Purchase price - I bought my new '03 naked SV1000 last fall for $5,500 out the door.
2. Cost of ownership - I'm no mechanic so the latter consideration was major for me. The SV1000 doesn't need it's valves checked until 15,000 miles. And it's really easy to do basic stuff like oil and spark plug changes and throttle body synchronization.
However, after I purchased the SV based mainly on the above criteria and since I had not ridden or even heard one, I was completely blown away by the rich amount of torque and the beautiful noise the bike made. I've definitely been converted to the twin.
I'm sure the Ducati and the Triumph are wonderful bikes too. They are both very pretty bikes to look at. But for the money, you can't touch the the SV1000. And IMHO, the SV is the best motorcycle I've ever owned.
Additionally, I recommend you join the SV1000 forum at www.sv1000.zyns.com
. Search around and ask questions and you will get honest and objective answers about the SV1000. That's a great website about motorcycling in general too.
Good luck in your new bike purchase!