Best Ranger and Assassin spells

[Bad Wolf]

Title says all. I'm looking for the all-around best spells for each class, both of which I don't have much experience Spell-wise.

[Nifft]

I'd suggest looking through the Chameleon Handbook (http://www.minmaxboards.com/index.php?topic=135).

It's got a nice write-up for the standout spells in both of those lists.

[flappeercraft]

For ranged rangers a spell I have not personally tried but seems really good on paper is Hunter's Mercy from SpC

[Inevitability]

Assassin's Darkness creates magical darkness only you can see through that lasts for minutes per level. It's pretty neat.

[Darrin]

Instant of Power (Forge of War). Immediate action, +4 bonus to your next attack, save, or damage roll. Get it in a wand, never leave home without it.

Blades of Fire (SC). TWF + fire.

Fire Shuriken (OA?). Creates magical throwing weapons. Instantaneous duration, so make 'em during down time and pile up a hoard.

[gorfnab]

There are some fairly good spell listings for the Ranger and Assassin in these handbooks:
3.5 Ranger Handbook (http://www.minmaxboards.com/index.php?topic=8684)
3.5 Assassin Handbook (http://www.minmaxboards.com/index.php?topic=8273)

The best choice of spells for either of these classes would also be based on the character build. Did you have a specific build in mind for these classes?

[Murmaider]

Fire Shuriken from SpC is pretty cool. If you have some spare time you can stockpile them. Just need some regular shuriken and pine sap.

I forgot the name of it, or where it was printed, butRanger has a spell that gives the caster sneak attack +1-6 per caster level. It's mediocre on Rangers, because of their usually low caster level. It's really good if you can get it on a full caster someway.

[Crake]

I personally like the assassin spell deathsight that lets you death attack without 3 rounds of observation. It's a standard action, and only lasts for your next attack, but with a rod of quicken, you can drop it to a swift action and death attack "spontaneously" 3 times a day.

Alternatively, you can combine it with sniper's shot (a 1st level assassin spell) which lets you sneak attack from any range, sniper's eye, which lets you deah attack with ranged attacks, and true strike, to shoot from your max range increment with an overall +2 bonus to death attack an enemy from something like a quarter of a mile away XD

[StreamOfTheSky]

For Ranger, my favorites are:
1st level: Arrow Mind, Embrace the Wild, Hunter's Mercy, Linked Perception, Resist Energy (b/c it's only 1st level), Rhino's Rush
2nd level: Camouflage (Mass), Fell the Greatest Foe, Hunter's Eye, Listening Lorecall, Tremorsense
3rd level: Arrow Storm / Blade Storm, Decoy Image, Find the Gap, Heal Animal Companion
4th level: Freedom of Movement

Hunter's Eye and Linked Perception are in PHB2, Resist Energy and Freedom of Movement are in the PHB, all the others are in Spell Compendium. Core ranger spells are awful.

Many of them are CL-dependent, so Practiced Spellcaster to make up for the awful 1/2 level progression is imperative.