I've just bought, 2 weeks ago, the 750 watt one from Argos (710-5362).
It was in the sale at £29.99 but just looked and it's back at £39.99.
I've used it twice for breaking concrete and it's 'paid for itself'
already in the time saved. It comes with a flat chisel, pointed chisel,
10/12 and 22mm SDS bits (IIRC) and a SDS chuck adaptor and keyed chuck.
It's a heavy beast so wouldn't like to be holding it all day, but they
all seem to be similar in size etc. After using it I would definately
recommend it to anyone. I bought it with these two jobs in mind and
thought if I get these done I'll be happy, I still have the drill for
future use so "job's a good un".

HTH

John