I currently have a site that's hosted in Texas.
The majority of my users are from Egypt and I'm a bit concerned that the current hosting is not the optimal in terms of performance. The site is not slow but for how can I know if, for example, hosting it in Europe or Asia is better ?
To clarify I need to know there is a way that I can test different hosting options - for example how can I test the average response time between Egypt and a host in Texas, the average response time between Egypt and a host in the UK ?
You can test the performance with http://www.alertfox.com/Tools/LoadTime/ from different locations.
you can ask for subjective opinions, you can ask someone there to use tools like yslow or google's load time analyzer but they will only provide you values [and maybe hints what to tweak] - it'll be up to you to decide if 1-2s of load time is good enough or not.
google and others have done lots of studies and load time seems to be pretty crucial for the end-users.
depending on type of your site - you can consider moving it to European hosting [for dynamic content] and using CDN for moving static content closer to the end user.
gomez and distributed testing networks can provide this
There are several providers which will measure your performance externally (e.g. Pingdom). You will need to find one with measure stations near your users.