This is a super common question, and folks generally don't like the answer.  I'll try to soften the blow a bit, but I'll start with the bad news.  If your fireplace is an older style, louvered, small unattractive logs, and a super weak flame, there's probably almost nothing you can do to the fireplace itself.  The basic reason why is that every fireplace on the market is tested in specific configurations, and then listed with a testing agency like UL or Intertek.  Anything you can do to the mechanical, electrical, or gas systems of that fireplace would then void the listing.  That means essentially that we can no longer say that the fireplace is 100% safe.  And even 1% is too much risk when dealing with the risk of a potentially deadly house fire.  That even applies to things like the log sets and brick liners.  If the manufacturer doesn't have the option to change it, it can't be changed.  Most manufacturers commit to producing parts for discontinued fireplaces for about 15 years.  So if you have an old B-Vent from the mid-90s, you're pretty stuck.  You could have someone touch up the paint, clean the glass, clean out the burner ports to help a bit, but these would be pretty minor changes. 

You could change out the surrounds though, so hey, that's something.  A lot of track homes or spec homes will have a very basic surround, which is essentially just some tile around the fireplace and on the floor in front of it.  They do this because 15-20 square feet of tile is really rather cheap, and they're looking out for the bottom line.  You certainly could replace that with a nice stone or wood mantel (respect the clearances if it's wood), or some attractive slate, marble, or ledgestone.  The trouble with that is, the fireplace that's behind the wall is larger than the surround.  That means if the fireplace eventually does go kaput, and replacement parts are no longer available, you'll have to redo the surround again to pull out and replace the fireplace.  So as long as you're opening that wall up, now's the time to put a new fireplace in it.  That way you can select options like upgraded burners for better heat output, blowers, accent lights, different log sets, brick liners, faceplates, even things like home automation.  Then you'll have a beautiful fireplace and a beautiful surround.  Get your HELOC ready though, because it's going to cost you 15-20k to get that done.  Best time to do it is when you're doing a kitchen or bathroom, and already have someone there who can do the adjustments to plumbing, a bit of wall patching, painting, and ha sort of thing.  That makes the process quite a bit more economical than calling in a contractor to do this as a stand-alone project. 

The moral of the story, I suppose, is that you can put some lipstick on that old thing, but there's no alchemy that can turn it into gold.  To find out what you can do, get the manufacturer, model, and serial number, call up your local dealer and see what options you have.  Short of that, just sit close and get cozy.