OK, from the specs you list above IMO the most useful is the video/audio in.
Why? Well if you are going to be doing editing of your video on a PC/Mac then you can use the analogue inputs (AV-in) to capture footage from a VCR or old analogue camcorder. Of course, if you don't intend to edit on the PC then you will not need this feature - but then again, who knows what they will want in the not too distant future!
Super night shot could be handy, but
AFAIK the PQ useing this is fairly low, but some people like it. Yet again it is down to wheather you think you will be recording at night with little light.
All the special effects recording options are IMO a waiste of time. They look good when you first start playing with them, but you soon get bored and stop useing them. IMO you are better off creating effects with editing software on a PC.
Memory stick capture is for putting still images onto removeable memory cards, making it easier to get the photos onto a PC. Photos from a camcorder are low quality compared to even a low cost digital camera, but they can be handy at times.
IMO the extra £54 is well worth paying just for the AV-in. But as I said above, only if you think you will have a need for it.
Good luck with the choice. Let us know what you decide, and feel free to ask if you have any more questions.
Mark.