I don't think anyone mentioned this yet, and maybe you already know, but if you want to use shoot .38 specials, you're basically limited to revolvers. I don't know of any semi-auto guns that shoot .38 specials (not mainstream ones anyway).
Of those revolvers, some are single action, some are double action, and some are double action only. (I don't mean to insult your intelligence if you already know this, but I figure I'd mention it in case you don't)
Single action (SA)--you must manually cock the hammer and then pull the trigger to shoot
Double action (DA)--you
can manually cock the hammer and then pull the trigger to shoot
or you can just pull the trigger to bring back the hammer and fire in one trigger pull (this requires a longer, heavier trigger pull)
Double action only (DAO)--these guns lack an accessible external hammer, so they can't be cocked prior to pulling the trigger.
Most people would prefer a DA or DAO revolver for defense.
S&W and
Ruger might be the most common revolver options today.
Charter Arms and
Taurus would be among the less expensive brands. There are a lot of used .38 special revolvers out on the market (particularly S&Ws) that some people would prefer over newer models.
I'm repeating some of what ckpj99 said, but if you want to go really small and light, the Ruger LCR, some of the polymer/aluminum S&W J-frame revolvers, and Charter Arms Undercover Lite models might interest you.
Steel J-frames and Charter Arms Undercover (non-Lite models) have more heft but are not bigger.
Next up in size might be Ruger SP101 revolvers, then S&W K-frame revolvers, and then you start getting into the Ruger GP100 and S&W 686, which are probably bulkier than necessary for .38 special.
Taurus makes revolvers of many different weights and sizes (more than I care to keep track of)
This isn't a comprehensive list of possibilities by any means. There are very high end options and many used guns and other lesser known brands I'm missing, but the above are some of the options I considered before I bought my first revolver.
*Again, sorry if this is all old, worthless information to you.