I've played my Gnome Bard up to level 17 now. I started at level one just on a lark. I thought I'd get bored with a bard and have him die in battle, but he's really grown on me.
My party's make up is very similar to yours.
Fighter/Occult Slayer
Fighter/Cleric
Sorceror/Dragon Disciple
That works out to about 2.5 fighter-types now that the DD has completed Dragon Disciple.
In a group like that, Bardic Music is HUGE.
I play my bard as a support unit. Sure, I don't have fireballs and such, but with Lingering Song I can "pre-buff" with one song, and switch to another. Inspire Greatness and Inspire Courage make a nice combo.
My spell selection has purposefully been geared towards helping the fighters do their job, and helping me avoid trouble. Spells like Tasa's Hideous Laughter, Heroism, Shatter, Dispel Magic, etc. have all saved our bacon many times over. And if I really need to dish out the damage, the Sorc/DD has made me a wand of fireballs. Use Magic Device is a class skill for a Bard, so if I need to blast, I can.
I also serve as the party's lock & trap man. Sure they're cross-class skills, but with a decent Int and Dex, I can handle them better than the others. I also spent some coin on a Chime of Opening which has come in handy.
I also am the default "face-man" for the team. I do the talking when we encounter NPC's. I have maxed ranks in Bluff and Diplomacy. I also augmented my Bluff Skill with a Choker of Eloquence, as well as the Charlatan, and Skill Focus: Bluff Feats. I can usually convince people that the sky is pink.
Since I've picked up all the Healing spells available to the bard, I'm the backup healer as well. My main goal is to keep enough healing spells to get the Cleric back on his feat after a fight if he's ever dropped. Once he's active again, he can handle the "heavy lifting".
With the Obscure Lore feat, and the synergy bonus for 5+ ranks in Knowledge: History, I'm also the only "detective" the team has. If your DM is willing to give you some leeway, Bardic Knowledge can be a huge advantage. But, you need to be constantly suggesting its use. Don't wait for the DM to call for a Bardic Knowledge check. Ask for one wenever you encouner something new. "Have I ever heard of this monster?" "Would I know any of its weaknesses?" etc. Access to Identify, and Legend Lore also helps.
Iproved Counterspell was a good investment as well. Since I have such a wide variety of spells, and can spontaneously cast, AND have a caster level equal to my bard level, I am a darn good counterspeller! And if that doesn't work, I have access to Dispel Magic and Greater Dispel Magic, which solve a lot of problems.
As for avoiding the "rapier fop" image. I play a dreadlocked gnome who has introduced hip-hop to the world. I pack a light crossbow and a longspear. My gnome racial ability of Ghost sound even provides a backbeat while I perform. I see him as a kind of
Capoeirista, using music to drive his fighting style, and urge on his comrades.
Hope this helps. I too was once a bard hater, but I have seen the light!