Wow... good comparo, I test drove all three of those because I was looking at those. I'm not sure if you realise this but in your comparo you have the base model Civic VTi which is considerably cheaper than the others which are the premium models. Nonetheless I'd pick the Civic not just on price but for other reasons... although it depends on the transmission too. Don't forget to try out the new Corolla if you are manual since it comes with a slick 6 speed.
1. Civic VTi (there's a reason why I bought this one in the end- in VTi-L)
Pros: Excellent build, most awesome interior of the lot (the speedo, the dash, the seats, etc.. everything is good quality), nicest steering wheel (if you get VTi-L/sport you get steering wheel controls), very nice engine/transmission/drivetrain combination in the automatic giving it sufficiently good drive & I like the handling (although it's not as sporty as other cars), comfortable to sit in.
(For your comparison though, you should've picked the Sport to make it more 'even' in comparison... since it'll have the mp3 stacker, leather interior, sunroof, 2.0L engine, etc..; but for your choices, the Civic is by far the best value for money here)
Cons: Handbrake is awkward location, crap stock headlights across the range (swap these for aftermarket bulbs asap), in the VTi you're getting steel wheels (which is expected in base model?), Not much torque so you need to learn to drive the Civic to make the most of it in the VTi/VTi-L (1.8L), VTi has very basic safety features (only 2 airbags)
2. Astra Coupe CDX (I was heart set on this car until I drove it)
Pros: Looks very sweet, has alot of features, great sound system for stock, superb build quality and strength (better than the Civic I'd say), great handling, cheap to run/maintain, good warranty from memory, has a good safety record too
Cons: Automatic is undriveable with the 1.8L/4speed Ecotec engine (it's horribly slow, there's a huge delay when accelerating!, sound system/computer in the CDX is difficult and confusing to use (and this is in comparison to say.. BMW's iDrive), interior is a bit dark for my liking but still comfortable, crap rear vision
3. Focus Zetec (The plastics in the demo car were falling off and the seat belt feeder was damaged- and the dealer told us this was a relatively new demo before we got in.... >__> )
Pros: 2.0L engine has plenty of up and go... handling also quite good from memory. Shouldn't be too exp since price drops on the Zetec are plentiful; however resale value will be affected significantly. Transmission module was pretty good too- not as amazingly brilliant as the Civic though.
Cons: Build quality is so shate you won't even want to sit in it, let alone drive it. User-features seem friendly to operate but are so flimsy looking you'll avoid touching things in case you worry you might snap them or something. Not many features or gizmos either; very bland interior compared to the Civic and Astra.
Hope this helps. Btw if you're looking at auto, the new Corolla is only a 4 speeder so I'd daresay it's in the same league as the Astra.