There are 40 Pokémon with 500 or more Base Stat in the Unova Pokedex. That means there are 116 Pokémon with less than 500, so I will just list the over 500 ones. EDIT I have now added all of the Unova Dex

From best to worse:

White Kyurem 700

Black Kyurem 700

Reshiram 680

Zekrom 680

Kyurem Normal form 660

Victini 600

Hydreigon 600

Landorus Incarnate 600

Landorus-Therian 600

Meloetta Aria form 600

Meloetta Pirouette form 600

Genesect 600

Cobalion 580

Terrakion 580

Virizion 580

Tornadus-Incarnate form 580

Tornadus-Therian form 580

Thundurus-Incarnate form 580

Thundurus-Therian form 580

Keldeo 580

Keldeo Resolute 580

Archeops 567

Volcarona 550

Darmanitan Zen Mode 540

Haxorus 540

Vanilluxe 535

Serperior 528

Emboar 528

Samurott 528

Klinklang 520

Chandelure 520

Eelektross 515

Zoroark 510

Mienshao 510

Braviary 510

Mandibuzz 510

Krookodile 509

Excadrill 508

Gigalith 505

Conkeldurr 505

Source: http://pokemondb.net/pokedex/black-white-stats

EDIT: Here is the list of below 500 Pokémon.

Seismitoad 499

Simisage 498

Simisear 498

Simipour 498

Zebstrika 497

Carracosta 495

Escavalier 495

Accelgor 495

Stoutland 490

Leavanny 490

Sigilyph 490

Gothitelle 490

Reuniclus 490

Bisharp 490

Bouffalant 490

Ferrothorn 489

Scrafty 488

Musharna 487

Beheeyem 485

Beartic 485

Cryogonal 485

Druddigon 485

Heatmor 484

Durant 484

Cofagrigus 483

Golurk 483

Whimsicott 480

Lilligant 480

Darmanitan Standard Mode 480

Jellicent 480

Unfezant 478

Scolipede 475

Crustle 475

Sawsbuck 475

Garbodor 475

Swanna 473

Galvantula 472

Stunfisk 471

Cinccino 470

Alomomola 470

Throh 465

Sawk 465

Amoonguss 464

Maractus 461

Basculin 460

Liepard 446

Audino 445

Klang 440

Emolga 428

Swoobat 425

Watchog 420

Zweilous 420

Pignite 418

Servine 413

Dewott 413

Fraxure 410

Gurdurr 405

Eelektrik 405

Archen 401

Vanillish 395

Boldore 390

Gothorita 390

Palpitoad 384

Swadloon 380

Herdier 370

Duosion 370

Lampent 370

Vullaby 370

Whirlipede 360

Larvesta 360

Tranquill 358

Tirtouga 355

Krokorok 351

Mienfoo 350

Rufflet 350

Scraggy 348

Pawniard 340

Deerling 335

Frillish 335

Elgyem 335

Zorua 330

Trubbish 329

Drilbur 328

Dwebble 325

Axew 320

Joltik 319

Pansage 316

Pansear 316

Panpour 316

Darumaka 315

Karrablast 315

Woobat 313

Sewaddle 310

Snivy 308

Tepig 308

Oshawott 308

Timburr 305

Ducklett 305

Vanillite 305

Ferroseed 305

Cubchoo 305

Shelmet 305

Yamask 303

Golett 303

Minccino 300

Klink 300

Deino 300

Blitzle 295

Tympole 294

Foongus 294

Munna 292

Sandile 292

Gothita 290

Solosis 290

Purrloin 281

Roggenrola 280

Cottonee 280

Petilil 280

Lillipup 275

Tynamo 275

Litwick 275

Pidove 264

Venipede 260

Patrat 255