in general? its been ten years since I applied for any kind of job and i've applied for about 20 in the last 2 weeks and having only had 1 reply back (from the first thing I looked into) i'm sat here waiting for more...is there a rule of thumb?

some will tell you in the job advert (I have applied for some that have said "if you havent heard within 2 weeks assume you were unsucessful"), but I would say you were within your rights to chase them up and enquire whether you have been shorlisted about 2 weeks after the closing date.
Also, depending on the type of job they quite often dont ask for references unless you are shortlisted, so you could ask your referees if they have had any requests.
good luck with finding something!

it depends ive had quick responsed from some of mine but none at all from others

One place I applied for a job at responded immediately, and because i couldnt get there to take an interview that day they sent their supervisor to my house to interview me.
I got the job.


Smug...

In the last 20 years the attitude towards job applicants from potential employers has changed.
Whilst there was a time when you would hear from an employer telling you if you had not been successful, this is no longer the case.
I have had the experience several times in recent years where I have been to an interview (even up to third interview stage) and never heard anything back from them.
On each occasion I have attempted to follow up with a phone call to the person who interviewed me, only to find them repeatedly unavailable.
I have now adopted the attitude of "If the have no common courtisy or manners I wouldn't want to work for them anyway!"

So, back on topic. I would take hearing nothing as a no.

from recent experience unless youve heard something within 2-4 weeks after the job applicationn closing date assume youve not got it

It depends when there closing date is but if you have not heard anything after a month, then forget about it!!