Yeast Size
Yeast is the model eukaryote.
The cell wall makes up 10-25% of the dry mass; the nucleus makes up 10% of the cell volume. Interestingly, it can be haploid and diploid. The diploid variant is larger, therefore, because the nucleus makes up significant volume.
Yeast can be thought of as spheres, on the order of $10^{-6}m$ length scale, putting it in company with E. Coli (note, however, that e. coli. is still significantly smaller). However, the median cell volume is highly dependent on certain genes, and can halve or double if certain genese are deleted.
For an interesting visual comparing e. coli to a sample yeast cells, see Cell Sizes.