What are the ploidy levels in major groups of organisms?
Are all animals haploid (n=x) ?


No


  Are all fungi haploid (n=x) ?


No


  Are all plants diploid (2n=x) ?


No


  Are all Protists diploid (2n=x) ?


No


  Also, what is the ploidy of archaea and bacteria?


Generally speaking, Bacteria and Archaea don't have chromosomes (but have circular DNA). As such the question of ploidy does not really apply to them.

You might want to read about Biological life cycle to understand the terms haplontic, diplontic, haplodiplontic (and other similar terms).

Ploidy level can easily varies among species of the same family (typically in plants for which hybridization is common). There is no reason to expect that a taxon as big as "fungi" (for example) would all have the same level of ploidy.

Note that your question that all animals are haploids is surprising as you just described that humans are diploids.