A couple things about the Paladin to bring up.
The Lawful Good restriction is not a shackle. A Paladin may deviate from the Lawful Good alignment. However, if they do so, they lose their class abilities and cannot take further levels in Paladin until they have atoned.
Also, they may never multiclass. If a Paladin takes levels in another class, they may never raise in Paladin again. Per the PHB:
These are the most prominent class restrictions. I am not passing judgement on any part of the system, just wanted that clearly stated since it's been a point of debate for the past couple of pages.
If you'd like to play an evil Paladin, I believe there are rules for anti-Paladins in Sword and Fist, the complete warrior sourcebook, as well as rules for evil Rangers, etc.
As far as spells, spell progression is the same for Paladins as it is for the Ranger, they just have access to different spells. As far as healing in combat, the Ranger and Paladin gain Cure Light, Cure Moderate and Cure Serious at the exact same levels.
Combat - The Paladin can wear heavy armor, but by 13th level a Ranger who took Two-Weapon Fighting for his combat style has SIX attacks per round, to the Paladin's 3. The Paladin can take Two-Weapon fighting and the associated feats, but the Ranger does so without sacraficing any feats. Combined with Weapon Finesse and the high dexterity that is so useful to a Ranger, the Ranger has a pretty good chance of taking down the Paladin in melee.
At range, of course, the Ranger has the advantage since he won't be wearing heavy armor and thus will be able to use his full Dex bonus (assuming Dex is 18 or less), in addition to only having a minor armor check penalty. With the high number of skill points allotted to Rangers in 3.5e, the Ranger is a excellent at sniping from cover, and the Paladin in his heavy armor simply cannot keep up.
Is a Ranger a good line trooper? Not really; like I said it's a tank versus a Humvee. But Rangers can certainly hold their own in melee or in the city, and will always be Masters of the Wild.