I have a soft spot for expanded A500s, though I have never used WHDload. All of the above are good options. Here are some other possibilities.
+1 to upgrade to KS3.1. Install OS3.1 and BetterWB on the HD.
I like lots of Fast ram. Supra's 500RX can go between the A590 & A500, might look clunky. There are memory expansions that mount beneath the 68000 (or 68010). I don't know if they are compat. with the A590.
The A590 resells because it was made by Commodore. If you can find them, Supra, GVP and others made more capable sidecars. You might consider moving up. Supra made a SCSI interface, 28 Mhz accelerator, and Fast ram expansion. Sadly, all 3 don't come in the same case.
