If you're unhappy with what you have now (020 & fast ram), you're going to want an 030 board for sure. Save up and get a quality model with a 40mhz or higher processor & at least 16mb ram. Be careful though... soon after that, you may get the upgrade itch again when you've had a little taste of how fast the Amiga OS can seem :-) If you stick mostly with games and some light Amiga desktop usage, an 030 will be just fine. If you're going to want to do some more serious desktop apps or are impatient, you may want to go full tilt and get a 1260 (060) board. My opinions:
OS 3.1 - 020 and fast ram is great, especially if you're mostly just playing games.
OS 3.9 - 030 and 32mb is the way to go for the ultra long directories of WHDload and decompression of files.