My own thoughts on this: fighter and cleric combine very nicely. However, before you set out on that road, you need to decide whether you want to be a fighter/cleric, a cleric/fighter, or a fighting cleric.
A fighter/cleric is primarily a fighter. If you start with Ftr 20 as your baseline, you can take 4 levels of cleric and lose 4hp, 2 feats, and 1 point of BAB for domain powers, +3 will, +2 fort, turn undead (useful for powering divine feats), the ability to use wands, the ability to try to use scrolls, and the ability to cast 2nd level spells (which while not that impressive at 20th level, will come in handy on your way to getting there and will occasionally be useful when you are 20th level). You could also take 8 levels of cleric and exchange another point of BAB, 2 more feats, and 4 more hp for another +1 will, better domain powers and the ability to cast 4th level spells. Divine Might is a good way to crank the damage of a one-handed weapon--especially at higher levels where it's much cheaper to buy an item to increase your charisma by 4 than to buy inherent bonusses to increase your strength by two. Divine Vigor can provide extra speed and temporary hit points. Domain powers like Destruction open new avenues for you (Extra Smiting for instance) and other powers like Travel Domain or the Luck Domain can help to cover a fighter's vulnerabilities.
As a fighter/cleric, your role in a group is almost always that of a fighter. You step up to the front, you apply the beatdown, you get beat on in return. Your spells will almost entirely be long duration buffs and utility spells. Freedom of Movement works well at caster level 7 and is not effected by SR. Air Walk is a good tactical option. Death Ward is nifty even at your low caster level, etc. After combat healing also doesn't care if it comes in the form of a heal spell of four cure serious wounds spells.
Fighter/cleric is not usually a real power-gaming option since most of the buffs you can cast will be pretty trivial for the party cleric to cast if you've got one. And his buffs will be more effective. The combination is at its best in an irregular or unusual group where you sometimes have to make do without a real cleric or the cleric in question isn't a team player. A party of three characters might find the added spellpower helpful. It's also a decent choice for a solo adventure.
Cleric/fighters are multiclass spellcasters who focus on the spellcasting end of the equation. Such characters will almost never have more than four levels of fighter (for +16 BAB at 20th level) and will usually have only one or two. As extremely martial clerics, they will usually spend as many of their spells as possible on long-term buffs and keep a few quickened spells in their pocket along with Righteous Might.
Cleric/Fighters fill the role of a cleric in a party but can also fill the role of a fighter without missing a beat. The primary difference between them and the fighter/clerics are these: they use righteous might and divine power (fighter/clerics never qualify for them) and they need to use those spells to fill the combat role. Fighter/clerics find buffs helpful but are focussed enough on combat that they generally don't need them. They are a decent power-gaming choice but IMO battle clerics are better. Generally, their fighter levels are aimed at qualifying for a full BAB/nearly full spellcasting prestige class like the 3.0 Hospitaller. A 3.5 Hospitaller would be good too but loses too many caster levels for a cleric/fighter to take the class all the way to 10th level.
Battle clerics are clerics who spend their feats and select their spells to be good at melee combat. They may take prestige classes, but they take care not to lose any caster levels. Their spell selection is like a cleric/fighter but they have less flexibility in terms of feats and NEED to be seriously buffed if they're going to be on the front line. Most of them are quite capable of filling the healer/buffer/spellcaster role in a party though. There is, of course, a wide spectrum of focussedness for battle-clerics. A cleric with the war domain whose feats are power attack, cleave, quicken spell, combat expertise, Improved Trip, improved critical, power critical, and combat reflexes is a lot more focussed than a cleric who has power attack, quicken spell, weapon focus, empower spell, craft wondrous item, extra turning, Divine Spellpower, Spell Penetration, and Greater Spell penetration. The first cleric is (probably) noticably better at combat than the second but the second character has more non-weapon based options. Domain choices and stat distribution also play a role in this. A cleric with destruction and strength domains will usually be more combat focussed than one with Sun and Healing though nothing prevents you from making Mr. Sun and Healing into a battle cleric.
The truest conversion of a 1e/2e fighter/cleric would probably be a cleric/fighter. A fighter/cleric is more like a paladin. A battle cleric is pretty good too but is a better spellcaster than the 1e/2e fighter/cleric.
