You can consider the following (I only know these so there may be other blades out there to consider):
(1) Endura VG10 PE. PE cos you said utility and defense. If it's outdoor utility and defense, serrated is advantageous and there is also no need for resharpening often. This knife is light, has a 4 inch blade in very good steel and an even more dependable locking system. The fact that Spyderco has a trainer model for the Endura would lead one to assume that the Endura is just as capable a self-defense knife. Cost to you: $50
(2) Military S30V. Excellent steel, full flat grind for cutting efficiency and a strong liner lock. My only caveat is the handle for this knife is really BIG. Please handle before buying, if possible, to see if it suits you. Cost to you : $100 for a used one on the exchange section of the forums, if you can find it.
(3) Benchmade Stryker. 154CM, G10 handles, linerlock, tanto shape, v-ground. I don't know much about this, but the shape, materials scream self-defense. The tanto shape is less utility-friendly though.
(4) Al Mar Sere - if you can find a used one for under $100.
(5) The scheduled to be released in September/October Microtech Mini Socom Elite Manual. This is a framelock and come in 154CM steel. The blade grind and shape are both utility and self-defense oriented. 3.5 inch blade.
(6) Mini-Buck Striders in spearpoint (not tanto point). Paul Bos treated ATS34, super thick liners, sturdy construction. May not be the most efficient slicer due to the stronger but thicker blade, but definitely geared for tough (hence, defense) chores.
(7) Finally, pls definitely consider SOG Vision in G10 scales. Comes with the very good arc-lock (similar to Benchmade's axis lock), tanto blade and 1.5 inches of serrations (the only bad point. altho others may differ). The blade is 4 inches long and has a satin finish. Not a pry bar, but a good cutter, smooth and dangerous looking. The G10 models can often be found for under $100 in the after-sales market.
If you can't locate a G10 Vision for under $100, then you can consider the zytel-scaled SOG x-ray vision. Same charateristics as the G10 model, except it has a beadblasted blade and cheaper, zytel/FRN scales which are not as strong (but strong enough) as G10. You can get these new for under $80.