Some of the earlier beta releases had a problem that meant they
wouldn't fit onto a 700Mb CD but the final release does so that would
suggest you actually got one of the pre-release versions. Go directly
to Kubuntu to get the proper one...

http://www.kubuntu.org/getkubuntu

FWIW I find Kubuntu to be more in keeping with the way I work and the
change from Ubuntu 10.04 was relatively easy. Yes there are some areas
where they are different and needed some adjustment on my part but
nothing that was a 'deal-breaker' :-)

Only thing I found was that the 64bit version didn't get on with the
32bit printer driver for our Dell colour laser but I've not found any
issues using 32bit Ubuntu with 4Gb RAM - and if you are interested in
colour laser printing I can heartily recommend the Dell 1250c ( or the
1350cn / 1350cnw - same beast with network connectivity ). Refilling
the toners is incredibly easy and a full set of refills are very cheap
even all the way from Hong Kong !