My view on some of the really popular ships.
Python: A fantastic general purpose ship. Think of it as a T7 that can actually do decently well in a fight. Also only needs a medium pad. Even with the nerf still in full effect, one of my favorite ships to fly. but can be expensive to buy and outfit (my own python cost some 97 million, without a class A shield gen, as I had to use bi-weave to help mitigate the price of outfitting it). Can be a bit sluggish without engineered drives.
FDL: One of the 3 great combat ships. It is the middle of the road option, medium cost, decent firepower, decent agility, and decent durability. Only real drawback is the god-awful jump range. Also one of my favorite ships to fly.
Vulture: Another of the 3 great combat ships. It is the light option. Great agility, decent enough speed, a little lacking in the firepower department when compared to the FDL. Very cheap by comparison to the FDL. Biggest drawbacks are the jump range and power issues if you don't engineer the hell out of the powerplant.
Fed Corvette: The last of the 3 great combat ships. The heaviest of the bunch, it packs a bunch of firepower, decent outfitting options due to its rather high number of internal slots, decent enough jump range, and is tough as nails. However, it is big, slow, sluggish and stupidly expensive. (I may never own one) Oh, and it is a faction specific ship.
Cutter: kinda like the corvette, but is more defense oriented. I hear that docking it can be a little strange because all of the ship is behind you. I don't plan on owning one.
Conda: The Phython's big brother. Pretty much sums it up. Cost more than the python, less than the vette or cutter, lots of outfitting options. Kinda like a T9 that can actually put up a fight. Still rather slow and sluggish, and pretty costly, but it works.
FDS, FGS, FAS: All I know is that shooting down any of these in something smaller than a FDL can be a PITA. I have never flown any of these and don't really plan too.
Clipper: Same as the FDS family of ships. Facing one can be tedious, and I don't plan on ever having one.
Asp and Diamondback families: I lump all of these together because they are very similar ships. All are intended for exploration, but some have other uses. The Diamondback ships are a bit better for combat IMO, due to their smaller sizes. The Asp S is almost a transition from the cobra family into the Asp X. The Asp X is one of the best exploration ships, only out ranged by a properly set up Conda. The Asp X can also be decent in a fight, not great, but good enough. It can also be used for trading, as it can hold about the same amount of cargo as a T6, but has better range and defensive options.
Viper family: Two good introductory combat ships. pretty cheap to get either, I use a Viper mk IV when I want to play around with weapon combinations. The III is the more agile and cheaper of the two, but you can run into power management issues if you don't have engineer help. The IV is a bit tougher, doesn't have the power issues, is a bit more expensive, and is a bit slower. Neither are a bad choice. Both suffer from jump range issues without engineer mods.
Cobra family: Two great and relatively cheap general purpose ships. There isn't a job they can't do. Both can fight, haul, explore, what have you. Ok, maybe mining in these ships would be a pain, but whatever, not the point. I made my first 50 million using mainly a Cobra mk III. The mk III is one of the fastest ships in the game. The one I use for fuel rat rescues has a boost speed that is above 450 m/s and disappears from scanners once I get 200 m away. The mk III also is the more agile and the cheaper of the two. The mk IV is tougher, has more weapon slots (and better placement), has more internal options, but is slower, has a bit smaller jump range, and is a bit more expensive. Both ships have their use. I have kept my Cobra mk. III around because it is such a fun ship. If you don't have a cobra mk III or IV, go get one, either earn enough to buy and outfit one the way you want, or add it to your fleet. Might be my absolute favorite ship to fly.
T-whatever family/ keelback: Pure trading ships. Absolute rubbish in a fight, jump range is passable, defenses aren't that great. The keelback has the potential to fare okay in a fight, but still not that great. The only real saving grace is that all of these ships can have SLFs and the T6, keelback, and even the T7 are pretty cheap compared to the other ships that can equip SLF hangers. I have used both the 6 and the 7 in the past. The T series has one purpose and does that job well enough.