response 1 of 4:

May 16 04:50 UTC 1995

My all-time favorite has to be the directory utility, SID, by Timm
Martin.  I discovered it shortly after purchasing my first Amiga.
Besides being a marvelously easy way to accomplish tasks such as
locating, moving or copying files, creating directories, reading
text, viewing pictures, etc., it also taught me a lot about how the
Amiga and its file system works.

On all of the subsequent Amigas I purchased, SID was always one of
the first programs I installed.  I gladly paid the $25 shareware fee,
and urged all of my friends to do the same.  I began using the
Workbench 2.x version, SID 2, as soon as it became available.

I purchased Directory Opus 4.0 after reading a glowing review of it,
but was disappointed to discover that there was really nothing I
wanted to use it for that couldn't be accomplished just as easily
with SID.  I have DOpus installed on one of my A4000s, but our
second A4000 and all of our A2000s are still using SID.  It's one
of the few programs, like DPaint, whose icon I continually leave
out on the workbench screen.

response 3 of 4:

Mar 21 00:53 UTC 1998

  The single most useful upgrade you can get for an older Amiga is a chip RAM
upgrade.  The first A2000s I owned came with the 1Mb Agnus.  Frequently,
while working in DPaint for instance, I would get the dreaded "insufficient
memory" message.  This puzzled me at first, since I had already max-ed out
my 8Mb SupraRAM boards.  Then I equipped my A2000s with the MegaChip 2Mb
Agnus upgrade.  I never saw the "insufficient memory" message again.
  In the April '98 edition of Amazing Computing/Amiga, Software Hut was
advertising the MegaChip A500/2000 for 169.95.  If you only get one upgrade
for your A500, this is probably the one to get.

  Of course, more fast RAM would also be nice, as would a faster CPU than the
stock 68000, and also a harddrive.  In the same Software Hut ad I spied an
A500 accelerator for $209.95 with the following features:
  -68020/16Mhz CPU w/FPU socket; 8Mb on board RAM; 3.0 ROMs and software;
   IDE interface can mount internal 2.5" harddrive.

  Since this package does not include a harddrive, you'll need to add one.
Software Hut offers a 1.08 Gig 2.5" HD for $189.00.  For an A500, that much
harddrive may be overkill, since most Amiga programs take up very little
drive space as compared to their PC counterparts.  Computer Renaissance in
Ann Arbor has smaller refurbished 2.5" IDE drives for less than $100.

  So, in answer to your question, yes you can upgrade an A500.  At least
up to a point.  What you can't do is upgrade it to the AGA chipset.  Sorry
to be disheartening, but for the price of the above mentioned upgrades,
plus the going rate for a refurbished A500, you might as well get a new
A1200 with harddrive and Magic Pack bundled software, which is currently
selling for less than $600.