The Civic Si is a fun car to drive. Every time I get in the driver's seat, I smile to myself, even though I'm aware that fun doesn't mean winning over all of the other sporty cars on the road to the next signal light ('cause it is probably not going to happen).
For those of you considering the Si, this is my recommendation: test drive at least 4 Civic Si's (so you know when one of these is dead). And, conduct your test drive in two phases:
1) gentle, "everyday" driving - this also allows the engine to warm up, too.
2) then, rev it out! The red line is 8000. Make it go there. If possible, turn off A/C & roll the windows down for this phase.
The clutch. Overall an ease to work with.
The gear shift. The gates are easily felt. The action is crisp. (Only comes in 6-speed manual)
The engine. Every time I rev past 6000, I'm graced with the tones of a beautiful exhaust note. (If you are considering a Si, please research what VTEC is before test driving.)
The dashboard. Often referred to as controversial, I've never found myself distracted by its layout. Like many things Honda, it doesn't look right at first, but it actually makes a lot of sense when you use it ('02-'06 CR-V parking brake).
The Sound System, sub-woofer included.
Fuel Economy. It gets good economy for being a sporty car (considering Premium requirement).
Ok, now that I've praised the '09 Civic Si, I'm going to go on a brief rampage against Honda's recent choices.
Honda, you had a great thing going with the K20Z3. Why did you chuck it in favor of the auditory disappointment of the K24Z7? I know that a bunch of whiners wanted more torque, but (honestly) they should have known that when they bought their Si. It's not THAT torque-less.
The only truly unique (market-separating) feature of the '06-'11 Si is it's engine. Specifically, the metallic bark of the VTEC crossover. And the 8000rpm red line. The suspension is good, but not unique. If I wanted less revs and longer stroke (torque), I would have bought a K24A2 ('06 TSX or something).