There are so many options. The best way is to try as many as you can. I gave my bass amp away to a good friend that deserved it a few weeks ago and I miss it already. You can get by with just a plain D.I. tone, but a lot of the recordings nowadays blend clean and dirty mic'ed amp and D.I. tones. The BEST could be a combination of all 3. Nice preamps and outboard or pedal compressors, plugins, and mic'ed amp(s).
For pedals the Sansamp is the standard. The Darkglass pedals are worth looking into. Even an old POD X3 is a really good bass preamp. You could even plug the Radial D.I. direct to the P.A. if the transients aren't too crazy. There is a really cool compressor pedal called the Cali76.
For free plugins check out Sonic Anomoly, AdHd, Ignite Amps, TSE, and Poulin. I would also get Two Notes Wall of Sound and buy a few cabinets for around 8 bucks each. Get an SVT and a B15 and blend them with some guitar cabs. Or you could use an IR loader like NadIR and buy some 3rd party IR's.
All of the popular guitar plugin packages for guitar have cool bass stuff built in. The guitar amps can sound good with bass too. Check out the demo versions for Bias FX and Bias Amp, Helix Native, Overloud TH-U, Kazrog Thermionic, and IK SVX 1 and 2.
Your guitar amps like the Fenders or the JTM45 could be cool for bass with the right cab and mic.
Sorry for the long winded post. Trying to be helpful.
