Parker 45 (Various Copies)
Brand: Parker (American)
Model: 45 (GT and CT Shown)
Production: 1960-2007 (Pens shown, ~1960s)
Nib: Varies (14K Gold, Gold Plated Steel, Steel)
Filler: Squeeze Converter or Parker Cartridge
I found the Parker 45s to be more enjoyable to use than the one Parker 51 Vacumatic I had. The semi-hooded nibs perform rather well, especially the 14K Fine nib that had some nice spring to it. The integrated collector in the section keeps the pen flowing wet and performs well in everyday usage even with more saturated inks like Parker Penman Sapphire and Noodler's Liberty's Elysium. The pens are very easy to disassemble and clean (though some in the wild may be fragile if ink has set in over the years).
They came in a wide variety of colors and finishes, eventually I would like to get my hands on a 45 Flighter or one of the Harlequin models from the 1970s. The standard models are quite affordable and would easily make an everyday carry pen.