Recommended ram from this bunch of Corsair sticks?

Assuming I go down the route of a new rig with a Haswell CPU (probably with stock fan so no height issues) and Z87 Asus mobo, which of these Corsair sticks would you recommend? I have no real plans of over clocking but I really don't know the difference in the frequencies, whether I should opt for 1600Mhz, 1866Mhz or higher, and whether the heat sinks on the top are nothing more than design when it comes to using as they stand (or sit!):

8GB

Corsair Vengeance 8GB 1600MHz 9-9-9-24 CMZ8GX3M2A1600C9
http://www.overclockers.co.uk/showproduct.php?prodid=MY-299-CS&groupid=701&catid=8&subcat=1517
£59.99

Corsair Vengeance Low Profile 8GB 1600MHz 9-9-9-24 CML8GX3M2A1600C9
http://www.overclockers.co.uk/showproduct.php?prodid=MY-307-CS&groupid=701&catid=8&subcat=1517
£65.99

Corsair Vengeance 8GB 1866Mhz 9-10-9-27 CMZ8GX3M2A1866C9
http://www.overclockers.co.uk/showproduct.php?prodid=MY-292-CS&groupid=701&catid=8&subcat=1387
£71.99

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16GB


Corsair Vengeance 16GB 1600Mhz 10-10-10-27 CMZ16GX3M2A1600C10
http://www.overclockers.co.uk/showproduct.php?prodid=MY-313-CS&groupid=701&catid=8&subcat=1517
£119.99

Corsair Vengeance Low Profile 16GB 1600Mhz 10-10-10-27 CML16GX3M2A1600C10
http://www.overclockers.co.uk/showproduct.php?prodid=MY-347-CS&groupid=701&catid=8&subcat=1517
£119.99

Corsair Vengeance 16GB 1866Mhz 9-10-9-27 CMZ16GX3M2A1866C9
http://www.overclockers.co.uk/showproduct.php?prodid=MY-346-CS&groupid=701&catid=8&subcat=1387
£129.95

Also, based on the above using 2 sticks, could I then add a further 2 x 2GB Corsair 1600Mhz 9-9-9-24 1.65v from my existing rig once finished with to increase the memory, or would it cause incompatibility issues?

Id go with whichever is cheapest, the difference from 1600mhz to 1866mhz is slim to nil in everyday usage.

8gb 1866mhz for Haswell. Its only an extra £5 and Haswell benefits quite a lot from fast RAM.