It's going to be awfully tough for me to say goodbye to "Boston Legal."

I know, I know. It's the fifth season for the legal comedy/drama. Many of the antics have become predictable, especially the various misbehaviors of William Shatner's Denny Crane. And the series' mood swings — between near-slapstick comedy and highfalutin' preaching about various social ills — have only gotten more extreme; quick, somebody fetch these people a lithium!

I can't help it. When it's over, I'll miss all of "Boston Legal's" miscreants.

Especially Denny Crane. Confession: I was a Trekkie. Er, um, Trekker; yes, that's the more dignified term, isn't it? In my very early teens, I watched rerun after rerun of the original "Star Trek." I enjoyed the show's spirit of adventure and its cerebral (for TV, anyhow) science-fiction bent. At one point I thought I'd outgrown it but later in life found myself enjoying some of the movies and television spinoffs.

One thing I was sure of, though: William Shatner would never get past the shadow of his "Trek" character, Capt. James T. Kirk.

I was wrong. "Boston Legal" provided him the vehicle to do just that. Denny Crane's outrageous behavior — rampant sexism, endless claims that his "mad cow" disease absolves him of his reckless deeds, a penchant for shooting off firearms in inappropriate places — has allowed Shatner to indulge his love of broad comedy. When I'm watching an episode of "Boston Legal," I never even think about Capt. Kirk.

Except, of course, when the show's writers want me to do so. On several occasions, "Legal" scripts have included references to Shatner's "Trek" past. In one episode, while being arrested in a men's room (don't ask), Denny tried to speaker-phone a colleague — and the cell phone emitted the old "communicator" sound effect from TOS (that's "The Original Series" to you non-"Trek" fans).

But "Boston Legal" never has been a one-man band. Whatever the show's persistent flaws (and it's had many), the casting always has been superb. Anchored by James Spader, Candice Bergen and Shatner, the cast has at various times included John Larroquette, Monica Potter, Julie Bowen, Constance Zimmer, Taraji P. Henson and the terrifically funny/sinister (and yes, beautiful) Saffron Burrows.

Oh, and Rene Auberjonois. What, you don't know who Rene Auberjonois is? He played Odo on "Star Trek: Deep Space Nine." You know, the shape shifter! The guy who spent part of his life living in a bucket ... OK, never mind.

Most shows that play musical chairs with the cast to "Boston Legal's" extent really suffer. Somehow, this series has gotten away with it. Infusing the legal offices of Crane, Poole and Schmidt with new blood each season helped keep the core characters delightfully off balance.

Good example: Larroquette's arrival for the fourth season. As Carl Sack, he provided a new love interest for Candice Bergen's Shirley Schmidt, much to the consternation of Shatner's Shirley-smitten Crane. The Sack character also refused to go along with everyone else's tolerance of Crane — realizing, as others seemed not to, that Shatner's character was basically nuts.

Behind the comedy and oddball characters, "Boston Legal" often has been a very serious show, and this season is no exception. I was impressed with "Smoke Signals," the season premiere, which raised interesting questions about the tobacco industry's liabilities vs. personal responsibility for polluting one's lungs with toxins.

Last Monday's episode dealt with two major themes: the aggressive marketing schemes of the U.S. pharmaceutical industry and the requirement that voters in this country be at least 18 years of age. I found the treatment of the former subject a little didactic, which can happen on this show. But the latter was handled extremely well — to the point that I found myself being persuaded right out of my personal views on the issue without feeling that I had been emotionally manipulated.

Tell me: How often does mere television accomplish something like that? Well, it depends on what you watch, of course. But mindless seems to be the rule these days; it's great when you find exceptions.

Mostly, though, I watched "Boston Legal" simply because it was such wicked fun. Nobody — not even well-to-do, obnoxious, East Coast lawyers — gets to go around acting like this nowadays. Shatner's Crane has been the worst (or best) of the lot, but Spader's Alan Shore has been no slouch.