Crystal Case
Purchased off E-Bay cost £1.98 inc. delivery
As you can see from above picture crystal case is a clear hard plastic case which comes in 2 parts. Although this was only £1.98 from ebay first impressions are good. the case seems to be well made with cut outs in all the right places
The bottom half fits perfectly , it has two tabs on either side that when the phone is inserted holds it in place securely

A closer look at one of the tabs

The top half has two tabs either side to hold it in place also
In no way does this case hinder the opening and closing of the keyboard
In conclusion this case fits pefectly, It has cut outs for the speaker ,charger camera etc. Once on this case looks good, feels good too. It is tight and I dont think it will fall off easily infact I had to take it off to take the pictures and it was hard to remove.
The only real draw back i could see was it has thin strip going across center at bottom of screen which makes the two silver keys slighly harder to press. No real hardship for me because it also makes it hard to select them by accident.
Another nice thing about this case is I had noticed at times when I picked up phone the sound was well muted because my fingers was covering speaker, now that I have crystal case on this stops fingers totally blocking speaker and sound is not muted half as much.
So final thoughts
Only time will tell how good this case stands up to everyday life, but for now it looks good protects the phone and allows me access to all necessary places without removing case and for £1.98 delivered a real bargain
here is link to seller
Sony Ericsson Xperia X1 Crystal Clear Hard Case UK on eBay, also Cases Housing, For Nokia, Mobile Phone Cases Pouches, Mobile Home Phones (end time 02-Dec-08 16:09:53 GMT)
And No im not the Seller
Pictures were taken with my N95
UPDATE
Though this case looked and felt good I can now report that like most other crystal cases I have tried they are short lived.
For no apperant reason ,while in coat pocket I must have caught front cover at bottom right hand corner and it snapped cleanly and fell off, its obviously a week spot