A logo that represents anything to do with the legal industry should have the relevant colors, symbols, fonts, and other proper elements. The design style you choose would be based on the kind of firm you want to represent. Many legal firms usually have a lot of partners, so fitting all their names on a single logo may not be a good idea. It might be best to leave room for expansion or contraction by going for a standalone design. This could include a tagline and/or brand name for the company logo.
Your brand message for the logo should be one of a unique service. There are several legal firms specializing in all sorts of fields these days. You have to convey what sets you apart and makes you worth the client's investment. Your specialization should hence tell the audience what you're providing.
If you usually represent high-profile clients in professional corporate cases, go for a minimalist, elegant logo with a sleek, black and white design and a font like EngraversGolthic BT is suitable. Your target audience would usually be business professionals who want the assurance of expertise. If you're more into family law, a dark blue color or beige with gold tones can convey both seriousness and comfort. The font here could be something like Garamond, which is dignified but not intimidating. The target audience here would be families that are probably confused and in search of a comforting kind of legal guidance.
The symbols of your legal logo would also depend on what you're offering. A family dispute lawyer, for instance, might display a couple inside a regular scale. For technology based clientele, a blue logo with pixels under a hammer could immediately convey this message even without words.
If you're looking for the best legal logo to represent your firm, consult a professional logo graphic designer as soon as possible. Even a simple consultation could set you on the right path for the most effective logo.