Expressed in number of Base Pairs or Bytes, about how large is the simplest eukaryotic genome?
How much of this is 'junk-DNA' (non-coding)?
You asked about eukaryotes. The genome of the yeast Saccharomyces cerevisiae is 12.2 Mb.
The genome of the smallest free-living eukaryote, Ostreococcus tauri (a unicellular green alga) is 12.6 Mb
There are smaller eukaryotic genomes, but these are not free-living organisms they are intracellular parasites.
According to this: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/GenomeSizes.html The shortest DNA of a individually living cell is that of Mycoplasma genitalium at about 580000 base pairs. -But it's not eucariotic!