Pax
if the sorceror finds that ALL of his spells are useless, odds are, a wizard would too. Just as often.
With that said, unlike wizards, sorcerors tend to select spells based on multi-purpose usage. The best example I can remember from the core rules would be Glitterdust; at low levels, being able to blind your opponents is grand. At high levels, evenwhen the DC for the blinding is too low to be of anything but an occasional "bonus" effect ... the outlining of invisible targets for the melee and ranged figters to see (and, one hopes, kill) is still invaluable.
And that is the key to an efective sorceror. Youneed one, maybe two "blaster" type spells per level, and the rest ... should be utility spells. Preferably ALL of them, blaster and utility alike, should have multiple uses or applications.
Versatility of application within each single spell is what keeps a sorceror alive and fun to play.
Now yes, I've been in situations where my "best" spell was useless -- at 5th level, when my 2d-level repertoire consisted of Glitterdust and Melf's Acid Arrow ... and we were facing a black dragon.
Oh well, I pumped magic missiles, glitterdusts, and rays of frost into it. One spell down wasn't a killer, and it helped show everyone that my sorceror was NOT the be-all, end-all "blaster mage". Meanwhile, I took a back seat against that one foe; no biggie, noone can (nor should they) be in center spotlight for EVERY encounter.